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National B Series

Freshman Cup
rating: ***
Participants: 6
(1,500) 22.05 -- 68 hp
(2,500) 22.12 -- 113 hp
(3,500) 23.17 -- 151 hp
(4,000) 24.54 -- 163 hp
Silverstone Stowe Circuit
(1,500) 21.13 -- 71 hp
(2,500) 22.52 -- 111 hp
(3,500) 25.00 -- 140 hp
(4,000) 25.81 -- 155 hp  
Clubman Route 5
(1,500) 18.75 -- 80 hp
(2,500) 19.04 -- 126 hp
(3,500) 22.72 -- 154 hp
(4,000) 23.80 -- 168 hp
B-spec: add 50 to 60 hp at all tracks. Better-handling rear-drives should have some aftermarket part, such as Racing Suspension, removed for stock parts.    
Rear-drive sports cars (such as the Mazda MX-5 series, Nissan Fairlady, Toyota MRs, etc.) should be started 2nd or 3rd place. Truthfully, some challenge can still be found if these are not included.
If a less-challenging grid is sought, remove 10 hp or more. Don't spend too much time a the Freshman Cup looking for challenge though. Finding that perfect grid takes a long time.   
The Freshman Cup, aimed at "beginners in which all kinds of cars can compete," the game's info states. NOW is the time for to be crowned as King of Sunday racers, it tells us.
Uh. Does this mean there are two Sunday Cups?  
Good news is: money does get better now, despite the fact that the racing becomes abominably easier. I originally entered my Fiat Panda with the 68 horsepower last used during the Novice Championship, unsure if this would be enough or not.
And turns out, this sort of power was just about right. Welcome to Sunday Cup II, folks.
Judging from how they lean, dip, and dive as they corner, our Freshman enemies are back on their default suspensions, I am guessing. Their power seems factory stock, or maybe barely tuned, in the case of a Mazda Lantis perhaps. Rear-drives like the Mazda Roadster still have some advantage over front-drives, yet they don't always trounce the FFs.
The Freshman Cup rates at two stars from me, though, because most of the time, the drivers are too tame. It's rare that they'll attempt to pass one another, or sometimes even catch up to each other. It's like GT6 went from easy races to easier races. On the other hand, some wicked-fun races can be found, if the right grid gets searched for. That's where the three-star rating can possibly come from.
Either way, enjoy those paychecks.   
Two laps. Dozens of races and thousands of laps have been done here, for those who've been around since Gran Turismo 4. Most GT vets simply won't need any preparation or practice. The AI drives this track horribly, probably because their traction controls are dumbing them from more spectacular performances. Even so, they still brake multiple times during hairpins, when once is all that's needed.   
Silverstone, The Stowe Circuit
Three laps. A new track for me, though no doubt Silverstone has probably appeared in plenty other racing games. This track is similar to Tsukuba, in the sense that there are no hills, no blind turns, and it's quick and easy to learn its braking zones and cornering lines. Passing berths are wide. Mistakes can be made. Miss a braking zone? It'll probably be okay. You'll probably still win.
Clubman Stage Route 5
Three laps. Here's a classic now, for those craving some nostalgia. Clubman Route 5 is the very opposite of the two previous tracks. Everything is surrounded by walls and guardrails, several turns are blind (especially for n00bs), and the directors of Route 5 still prefer to hold their trials only at night. Carry as much speed into the tunnel area as possible; the others still brake into this dual turn too early. 
Soft Comfort Tires (A-spec)
Hard Sport Tires (B-spec)
Factory suspensions are sufficient under most cars, even for many Historics. Only those with some really disastrous cornering should opt for Racing Suspensions.
Close-ratio Transmission for many, especially at Tsukuba. The other two tracks might require factory gearing, with full-customized gears only needed for rare cases.
Twin-Plate Clutch Kit for many. Other drivetrain parts as needed.   
'90 Fiat Panda Super 1000S (1,500 pounds)
'00 Fiat Punto HGT Abarth   (2,500 pounds)
'98 Alfa Romeo 166 2.5 16v and '03 Honda Element (3,500 pounds)
'03 Honda Element                  (4,000 pounds)   

400 PP Clubman Cup
rating: **
Participants: 6
Silverstone National Circuit
(1,500) 19.48 -- 77 hp
(2,500) 21.17 -- 115 hp
(3,500) 22.47 -- 153 hp
(4,000) 21.98 -- 182 hp    
Circuito di Roma
(1,500) 20.00 -- 75 hp
(2,500) 22.93 -- 109 hp
(3,500) 24.47 -- 143 hp
(4,000) 24.53 -- 163 hp   
Autumn Ring
(1,500) 21.47 -- 70 hp
(2,500) 26.35 -- 95 hp
(3,500) 29.66 -- 118 hp
(4,000) 31.49 -- 127 hp
B-spec: add 50 to 65 at Silverstone or Rome, and 60 to 80 at Autumn Ring.     
For the most diverse competition, find grids which start rear-drive sport cars (MX-5s, RX-7s, MR2s, Renault 5 Turbo etc.) no higher than 2nd place. These grids can take awhile to find, but offer the most in-fighting between brands. 
There are a few front-drives(Acura RS-X, Acura Integra, Citroen C4, Mini Cooper S, etc.) which do better than other front-drives. These better FFs can be started on pole if more challenge is desired, and the races can still be won, though not as predictably.
If going up against easier grids that feature no top cars, remove 5 to 10 horsepower.    
In the past, the Clubman Cup used to be a rather daring set of events. In Gran Turismos 1, 2, and 4, the competition varied, the challenge was definitely there. Not the toughest set of events in the game, but certainly several steps up from the Sundays. An example from GT4: the Lotus Elise or Opel Speedster could show up as competition, and I recommended a lot of power to beat them.  
Well, here in GT6, the designation "400 PP" lends a really BIG clue that those cutthroat races of yore have not quite returned yet. (500 is actually the max, by the way). The Clubman of GT4 required anywhere from 209 to over 400 horsepower if the top car(s) showed up, and that was for "good-handling" cars.
So again, I have done my best to try to find some challenge. And hey, at least these races are a step up from the Freshman Cup.     
Though the racing is still easy, the crowd subtly changes. Skylines make more significant appearances for instance. So does the Acura RSX. The 1980 Renault 5, and so on. But a lot of the others from previous races also return: Silvias, Preludes, Celicas, FTOs, and so on. Amongst this list, again, nobody really shines above the rest. There is too much space between each car, meaning that there isn't much in-fighting between them.
As stated earlier, sometimes putting rear-drives on 2nd or 3rd place helps cure some of the predictability.
Silverstone National
Two laps, actually each track features just two laps. The National version of Silverstone is slightly more difficult than the Stowe version, mostly because there are three areas which feature high top speeds, followed by crawling through tight loops. But Silverstone National is also easy to learn, also features zero hills, and its turns are mostly not blind.
Circuito di Roma
Back in Rome, a walled city track. One of the tricks to Rome is constantly seeking for that perfect set of cornering lines through its wider turns, while avoiding slower competition. No matter which type of car gets driven (FF, FR, etc.) there is always some leeway during most of these longer turns. Still, it happens sometimes that a carefully-prepared orbit around some braindead loser can go wrong The most dreaded sound is that *thunk* which occurs after trying to get creative with looping around some other car, yet we don't quite make it without catching an inch or two its rear bumper.    
Autumn Ring
Autumn Ring is the odd track, where our opponents simply don't (or can't) try as hard as they do at Silverstone and Roma. Even with the power suggested, it may be a good idea to look for those toughest of grids, perhaps starting an alpha on pole, even, otherwise this particular track can be way too easy.
Soft Comfort Tires
Racing Suspensions (Hard or Soft, your call) at the first two tracks.. Many can simply use their factory parts at Autumn Ring.  
Close-ratio Transmission for many. Factory units can be left in place for those whose close-ratio gears are too short.
Twin Clutch Kit, and other assorted drivetrain parts, as needed.
Limited-slip Device for Historic cars.   
'90 Fiat Panda Super 1000 S (1,500)
'00 Fiat Punto HGT Abarth and '02 Mini One (2,500)
'98 Alfa Romeo 166                     (3,500)
'03 Honda Odyssey                   (4,000)  

City Trials
rating: *** (Tokyo)
            ** (Madrid and London)
Participants: six 
Circuito de Madrid
(1,500) 14.28 -- 105 hp
(2,000) 17.09 -- 117 hp
(2,500) 19.23 -- 130 hp
(3,500) 22.87 -- 153 hp
(4,000) 23.39 -- 171 hp   
Tokyo Route 246
(1,500) 10.06 -- 149 hp
(2,000) 11.92 -- 167 hp
(2,500) 13.25 -- 188 hp
(3,500) 15.02 -- 233 hp
(4,000) 15.15 -- 264 hp   
(1,500) 13.63 -- 110 hp
(2,000) 16.12 -- 124 hp
(2,500) 17.98 -- 139 hp
(3,500) 20.59 -- 170 hp
(4,000) 20.75 -- 183 hp     
Circuito de Madrid
(1,500) 13.64 -- 110 hp
(2,000) 16.38 -- 122 hp
(3,000) 19.87 -- 151 hp
(4,200) 19.09 -- 209 hp   
Tokyo Route 246
(1,500) 9.74 -- 153 hp
(2,000) 11.11 - 180 HP
(3,000) 13.64 - 220 hp
(4,200) 15.33 -- 274 hp
(1,500) 12.71 -- 118 hp
(2,000) 14.59 -- 137 hp
(3,000) 17.54 -- 171 hp
(4,200) 17.65 -- 238 hp  
Ratios above can be used with front or rear-drives.
Historic Class incudes those which would not have ABS brakes in real-life.
B-spec: add 150 or more at Madrid to front-drives and some all wheel-drives, 120 or more to RWD and AWD sports cars.
Add 80 hp or more at Tokyo, for all drivetrain types.
Add 150 or more to all drivetrain types at London.  
There are two classes of AI which can show up to City Trials, and one class is faster than the other. I am calling these Class 1 and Class 2.
Class 1: Start these no higher than 2nd place at Madrid or London, 4th place at Tokyo
any Honda NSX
'03 Honda S2000 Type V
'09 Toyota FT-86 Concept  
Class 2: Start these no higher than 2nd place at Madrid, and 3rd place at Tokyo
'07 Audi TT 3.2 Quattro
'09 Audi TTS
'97 Chevrolet Camaro Z28,
'96 Mazda RX-7 Type RS
'07 Mazda RX-8
any Nissan Z-car from the Z33 generation
any Renault Clio Sport V6
'10 Volkswagen Scirocco R 
If none of those faster cars show up at Tokyo, remove 10 horsepower.
This can also be applied to some better-handling cars, at this track, even if Class 2 shows up, starting as high as 2nd.    
Finally, anybody can be started anywhere at London, except for the NSX, S2000, or FT-86.
Three races, all held in cities: two in Europe, and one in Japan.
Pros: Those who've been craving more speed have finally got their wish
Cons: These events still don't require that much power to win. And there's still only six cars per race. I am missing GT5's extra two to six entrants; will larger grids eventually show up in this game?   
Good news is: everybody tries a little harder than they did during the Freshman and 400 PP. The level of excitement does get a little higher.   
Some of the better opponents of the Novice series (and into the 400 PP Cup) have had at least 160 horsepower, in theory. This game does not post anybody's stats, so that is just a guess. NB-era Mazda MX-5s start with about 160, so I feel that's a fair guess at the lower end. At the higher end are Integras and Preludes, which carry around or just above 200 hp. This same group of cars has been showing up ever since the Sunday Cup.   
Here during City Trials, the crowd suddenly changes. Take the Honda S2000 for instance. These hover somewhere around 240 horsepower. So does the '92 Mitsubishi Lancer, and Jaguar E-Type. PD also includes a few from Japan's "Gentlemen's Agreement" crowd ... most of which were factory rated at 276: a few Nissan Skylines, '97 Honda NSX, Mazda RX-7 Type RZ, '96 Mitsubishi Lancer Evo III, and so on. Finally, we've got some muscle: the '87 Buick GNX, Ford Mustang GT and Chevrolet Camaro are just over 280 horses.
It's hard to say exactly how much each car actually rates with power, since PD no longer bothers to post their specs. But a fair assessment is "somewhere between 240 and 300 horsepower" for sure. Some cars probably have had their power limited, others have had it boosted. On top of this, some handle better than others, some are more race-ready than others.
To boil it down, City Trials is the first set of events which includes a dual class system. Those which are faster usually include obvious sports car types, as well as one from the muscle crowd, and these are all listed below. 
'07 Audi TT 3.2 Quattro
'09 Audi TTS  
'97 Chevrolet Camaro Z28
'97 Honda NSX
'03 Honda S2000 Type V 
'96 Mazda RX-7 Type RS
'07 Mazda RX-8 Type S
'03 Nissan Fairlady Z
'03 Renault Clio Sport V6 
'09 Toyota FT-86 Concept
--Follow the rules which appear just under the math ratio area, for placement of these faster ones. 
-Anybody not on that list are slower machines, and can be started anywhere.  
Hard Sport Tires
Racing Suspension (Hard or Soft), those with stellar handling won't need this.
Fully Customizable Suspension for some Historic cars.
Racing Brakes for some from the Modern Class. Those from the Historic Class should have ABS off, and will be better off using Standard brakes. Neither class should have brake balancer on.  
Close-ratio gearing for many at Madrid and London. Route 246 typically requires taller boxes (typically whatever was installed from the dealer).
Twin-Plate Clutch Kit and/or Carbon Driveshaft. Some cars with slippery traction or wobbly maneuverability might need Fully Customized LSD.
'97 Daihatsu Mira TR-XX (Modern, 1,500)
''00 Toyota Yaris RS 1.5    (Modern, 2,000)
'00 Fiat Punto HGT Abarth (Modern, 2,500)
'98 Alfa Romeo 166          (Modern, 3,500)
'90 Fiat Panda Super 1000S (Historic, 1,500 pounds)
Math Calculation (no car)   (Historic, 2,000 pounds)
'86 Toyota Celica 2000 GT-R  (Historic, 2,900 pound)
'88 Volvo 240 GLT Estate    (Historic, 4,200 pounds)

5-Minute Races
rating: *** 
Participants: 6
Autumn Ring Mini
(1,500) 16.12 -- 93 hp
(2,000) 18.51 -- 108 hp
(2,500) 21.19 -- 118 hp
(3,000) 24.19 -- 124 hp
(4,200) 28.76 -- 146 hp     
(1,500) 17.04 -- 88 hp
(2,000) 19.80 -- 101 hp
(2,500) 22.52 -- 111 hp
(3,000) 25.00 -- 120 hp
(4,200) 27.67 -- 152 hp     
Circuito di Roma
(1,500) 15.62 -- 96 hp
(2,000) 17.54 -- 114 hp
(2,500) 20.00 -- 125 hp
(3,000) 20.22 -- 135 hp
(4,200) 25.00 -- 168 hp     
B-spec: add 120 hp at Autumn Ring, 100 at Tsukuba, 80 at Rome
All ratios (A or B-spec) apply to front or rear-drives. There originally were Modern and Historic classes for these, but the truth is there's little difference between cars with ABS and non-ABS brakes, at this level. Historics might need some better parts, that's all.
Start these cars on Pole
'82 Audi Quattro
any Honda Civic Type R
any Honda Integras
any Mini Coopers
any Nissan Silvias
any Nissan Skylines 
any Mazda RX-7s
'04 Seat Ibiza Cupra
Start these cars on 2nd place or lower.
any Mazda Miata, MX-5 or Roadster
any Toyota MR2 and MR-S
The 1980 Renault 5 Turbo is top alpha, especially at Rome. This can be started as low as 4th place and still challenge for the lead at the end.   
If none of these show, remove 10 horsepower or more.   
Now here's a series of races with a concept I did not expect.  Long ago in the days of GT2, there was an endurance race held at Rome with a 2 hour limit. Instead of a total number of laps to finish, one had to make sure he was in the lead just after 2 hours had passed.
The idea here in GT6 is pretty much the same, except these 5-miniute stints aren't long enough for tire wear to set in.  
It's like the game takes a step back with the ones we're up against, as challenge falls back to 400 PP levels. Some of the same faces from the beginnings of the game make returns: Nissan Silvias, Mini Coopers, Mazda Atenzas, and so on.
The most challenging pole-starters are the Mini Coopers and Honda Integras if we're talking front-drives. Older Nissan Skylines and '85 Mazda RX-7s can also be started on pole.
The sportier Mazda Roadsters and Toyota MRs make can be started on 2nd place for the most impact and greatest chance of position changes up front.
The '80 Renault 5 Turbo is the ultimate dominator though, especially at Rome.  
One weird thing: there definitely is some rubber-banding going on!  If we aren't approaching the leader(s) after X number of laps, they all start driving much slower, shaving multiple seconds from their own lap times. It's yet another reason why this racing guide works so well; I am finding that almost every race feels like a close one toward its end.
On the other hand, those who get an early lead will at least find those behind will tend to crowd those mirrors.    
Soft Comfort Tires
Racing Suspension for most Historics. Modern vehicles might only need these parts for those harder grids.
Close-ratio gearing for many at Autumn Ring Mini and Tsukuba. Rome may require taller gears.
Twin Clutch Kit, maybe a Carbon Driveshaft for rear-drives from the Historic era.  
'99 Toyota Yaris F        (2,000, Modern)
'00 Fiat Punto            (2,500, Modern)
90 Fiat Panda Super (1,500 pounds, Historic)
'65 Nissan Silvia    (2,000 pounds, Historic)
'88 Honda Accord Coupe: (3,000, Historic)
'88 Volvo 240 GLT Estate (4,200, Historic)   

Sunday Kart Jr. Races
rating: **
Participants: 6
Gran Turismo 5 started the whole karting thing, which were one-off stints aimed at honing the skills of early drivers, hosted in that game's Special Events section. Here in GT6, the SKJR is now part of the A-spec experience itself.
The big difference between both games mostly comes down to money. In GT5, more money was allotted per win, but this money could only be one once. In GT6, not nearly as much can be had per win, but at least these winnings are repeatable.
For extra realism and challenge, turn off the HUD! Turn off any music, too. No kart is going to have a GPS map after all, nor are they equipped with stereos!   
6 go-karts per track, rather than GT5's 16 (yes, sixteen). What this means is the sound and frame-rate drops of the previous game have been taken care of, but the chaotic feeling of having all those extra opponents is unfortunately gone.
Gran Turismo Arena (Layout A)
Three Laps. GTA is a tight track featuring mostly 90 degree turns and one short straight. Easy to learn, most drivers should have few problems acing this one in one or two shots    
Autumn Ring Mini
Two laps. This is the toughest course in my opinion, because ARM has some pretty drastic bumps and elevation changes which the other two tracks lack. Be careful when nudging over those blue and white curbs, as they can lift these lightweight machines with ease, causing stability issues.
Autumn Ring Mini also features just one significant braking zone: the very first turn, which is a hairpin. The rest of the time, drivers should be mostly flooring it if they want to win. Easier said than done, Autumn Ring Mini is the only attempt which might require practice. Another issue is the guys who show up are pretty good. GT5 separated these drivers into Beginner, Intermediate, and Advanced levels. GT6's drivers all seem like they're advanced.
Kart Space II
Real-life karting tracks can get away with silly themes and ideas not found on public roads, much less actual tracks made for actual cars. Sort of like miniature golf compared to real golf. Kart Space II is like this. This track is more like something out of Mario Kart than Gran Turismo. Goofy up-and-down lift/drop areas, disco lights, and lots of random spectators are all a part of the Kart Space experience.
Maybe the idea is all of these visual inputs are there to distract the driver, because those who can manage to focus can find rather easy wins to be had here.

FF Challenge
rating: **
Participants: 6
Tsukuba Circuit
(1,500) 15.46 -- 97 hp
(2,000) 18.69 -- 107 hp
(3,500) 26.51 -- 132 hp  
Deep Forest Raceway
(1,500) 19.48 -- 77 hp
(2,000) 18.87 -- 106 hp
(3,500) 26.31 -- 133 hp  
Twin Ring Motegi East Course
(1,500) 13.88 -- 108 hp  
(2,000) 15.87 -- 126 hp
(3,500) 22.58-- 155 hp
B-spec: +120 to 140 hp at all tracks.
Most front-drives are on the same page when it comes to competition. Start the Dodge SRT4, Ford Focus RS, any Honda Civic Type R from the 2000s, any Honda Integra Type R from the 2000s, and Volkswagen Scirocco R no higher than 2nd for the best track in-fighting.
Keep in mind that cross-competitive action amongst enemy drivers is not always guaranteed though. ;(  
Welcome to some action from the Fast & Furious crowd. The FF Challenge has always been on the lower-end of the GT series, so far as competition goes. With a max rating of 550 pp (rather than 450 or even 500), it might seem like just a little more will be needed here.
Good news is, compared to GT5, Gran Turismo 6 does require more.
Typical front-drive masters do a little better than the bulk of the FF crowd, all of whom get expected. These were mentioned above, but for convenience I'll repeat them again below.
'03 Dodge SRT4
'03 Ford Focus RS
'01 Honda Civic Type R
'08 Honda Civic Type R
'99 Honda Integra Type R
'04 Honda Integra Type R
'11 Renault Clio Sport 
'10 Volkswagen Scirocco R  
These won't always make their play against others successfully, but it's worth a try.
Soft Comfort Tires
Racing Suspension for most econoboxes. Front-drives which are sportier or which have had their power heavily limited won't need this.
Close-ratio gearing for most modern autos.
Twin-Plate Clutch Kit
Limited-slip device and/or Racing Brakes only for those with the very worst traction / stopping abilities. Most FFs will succeed here though, even those with so-so handling abilities.   
'97 Daihatsu Mira TR-XX Avanzato R (1,500)
'00 Toyota Yaris RS 1.5 (2,000)
'03 Mazda 6 sedan        (3,500)

FR Challenge
rating: *** 
Participants: 6
Grand Valley East
(2,000) 13.24 -- 151 hp
(3,000) 13.51 -- 222 hp

Trial Mountain
(2,000) 16.52 -- 121 hp
(3,000) 16.66 -- 180 hp

Silverstone Grand Prix Circuit
(2,000) 12.42 -- 161 hp
(3,000) 18.84 -- 230 hp

Grand Valley East
(2,000) 11.61 -- 171 hp 
(3,000) 12.19 -- 246 hp

Trial Mountain
(2,000) 13.42 -- 149 hp
(3,000) 13.16 -- 228 hp

Silverstone National
(2,000) 10.83 -- 183 hp
(3,000) 11.67 -- 257 hp

Certain cars need to be started no higher than 2nd or 3rd place. See Opponents section.

B-spec: +150 horsepower at Grand Valley East, +200 at trial Mountain, and +150 at Silverstone. Later-model cars are recommended ('07 Skyline instead of an '89 Skyline, for instance).

Now time for the front-engine / rear-drives. The FR Challenge does require more talent than the FF Challenge. Power gets increased, skills need to be honed, tuning is required, and (best of all) the pace gets quickened.  


The pace gets picked up again, yes. Everybody showing up is firmly rated over 276 horsepower for sure, and some could have way more than 276. This becomes quickly apparent when traveling down straights, when they blast right by with their hoards of extra power.

But they still have problems, the most annoying one is the way they brake: slowing way down during turns, braking when they shouldn't have to. Downright unprofessional. If the driver's in the wrong place at the wrong time, this causes him or her to ALSO need to use brakes, when I shouldn't have to.

So the idea is (once again) to be ready to get around them, in as many unorthodox ways as possible. This is not just to win the race, but also to avoid getting tangled into unfortunate accidents.

Here is the list of cars I'm noticing is faster than others. Again, start these ones on 2nd place (Grand Valley East & Trial Mountain) or 3rd place (Silverstone National).  


'08 Alfa Romeo 8C Competizione


'03 BMW M3 GTR

'08 BMW Z8

'10 Chevrolet Camaro Z28 

'00 Chevrolet Corvette

'13 Ford Mustang Boss 302

'00 Mazda RX-7 Type RZ

 Silverstone's Grand Prix version is the track which really rates some concern, for those who've never driven here. It is much more demanding and tricky to learn. Is that next curve coming up a left or a right?  Am I supposed to be in 2nd gear?  Wait, where's that braking zone again?

Something about the Grand Prix version can make a driver doubtful, as though we're learning Nurburgring all over again. Definitely take the time to practice here. One of the trickiest things about this track are its two main straight areas, with a sharp right turn at their very ends. Oftentimes, the only way I know which straight I'm on is to look at the clock!  If just over a minute has passed, that's the first straight / roughly half the track!    

Hard Sport Tires

Racing Suspension for some.

Racing Brakes for those that have trouble with 100 meters into the first hairpin of Grand Valley.

Gearing can vary widely. Full-custom gears should still be the last option though.

Twin-Plate Clutch-Kit and/or Carbon Driveshaft (esp. for low-torque engines) 

Limited-Slip Device for those that need it.

'89 Mazda MX-5 Miata               (2,000, Modern Class)
'89 Nissan Skyline GTS-5 Type M (3,000, Modern Class)
'70 Toyota Celica 1600GT     (2,000, Historic Class)
'63 Chevrolet Corvette Coupe (3,000, Historic Class)

Japanese '90s Challenge
rating: **
Participants: 6 
Clubman Route 5
(1,500) 13.16 -- 114 hp
(2,000) 15.27 -- 131 hp
(3,000) 19.07 -- 151 hp
Twin Ring Motegi East
(1,500) 11.28 -- 133 hp
(2,000) 12.98 -- 154 hp
(3,000) 16.38 -- 184 hp  
Tokyo Route 246
(1,500)  9.75 -- 157 hp
(2,000) 11.21 -- 178 hp
(3,000) 13.95 -- 215 hp
B-spec: add +150 to 200 hp  
Main enemy here is the Honda NSX, and up to two of these can show up on the same grid. Start these no higher than 2nd place at Clubman Route 5 or Twin Ring Motegi, for the above ratios to work best. Start them no higher than 3rd at Tokyo.  
Yes. I just entered a Toyota Yaris F into the Japanese '90s series.
By this point, I should be getting my ass handed to me in so many ways right? But it's just not happening yet. The Japanese '90s Challenge really is nothing to fear. Like GT5's version, I imagine those who wish to use Kei cars will only need to worry about which one to choose: a Honda Beat or Daihatsu Move? Lol.
Seriously though, the pale pink Toyota Yaris F I initially drove (same car which was won from GT5's Vitz / Yaris races) should be getting NOWHERE NEAR to the group of Lancers, Imprezas, and even NSXes which show up to this series. It should be getting trounced. It should be getting laughed at by the other virtual drivers, right!?!
So, all the ratios set above were made with the eonomites, the low-powered sprites, and so on. Those who try to enter an NSX, an RX-7, or even a base GTO may find themselves seriously bored. Not me though.      
As mentioned, a typical variety of JDM talent shows up, all the cars we'd expect, pretty much. The Honda NSX can be slightly faster than others sometimes, but unlike previous games, PD did a REALLY good job at ... whatever the hell they did to keep the NSX from just stomping ahead of everyone else.
My previous complaint about unprofessional driving still stands though. It's like they KNOW I'm about to pass them, they've already got the best line through a turn. So they make sure to brake just ahead (when braking is not needed), forcing me to choose some weird, quirky line that puts me heading toward some grass. Or even worse, a wall.
On a better note, one of the cool things about this series is PD also did an even better job at balancing everybody than they did for GT5, meaning it doesn't take very long to find a suitable grid to compete against.   
Hard Sport Tires
Racing Suspension
Close-ratio transmission for most, Some Keis will require factory boxes or Full-Custom units at all three tracks.
Twin-Plate Clutch Kit
Carbon driveshaft for rear-drives
Limited-slip Device especially at Twin Ring Motegi, though for some cars this can be overkill.
Racing Brakes for a lot of the crappy non-racing types I'm recommending (see below).
'97 Suzuki Alto Works RS-Z (1,500)
'99 Toyota Yaris F (2,000)
'91 Toyota Celica GT-R (3,000) 

Classic Sports Car Series
Participants: 6
Circuito de Madrid - Mini
(1,500) 12.71 -- 118 hp
(2,000) 14.70 -- 136 hp
(2,900) 18.95 -- 153 hp   
(1,500) 14.70 -- 102 hp
(2,000) 16.12 -- 124 hp
(2,900) 21.01 -- 138 hp  
Silverstone Grand Prix
(1,500) 14.28 -- 105 hp
(2,000) 15.74 -- 127 hp
(2,900) 20.42 -- 142 hp
B-spec: add 100 hp if any of the "Fast Four" show up, starting near pole (see guidelines below). This power can also be used if an Alpine, '63 Corvette, or either Mercedes 300SL starts on or near pole.. Remove 40 horsepower of more if none of these appear.   
The Lancia Stratos is the fastest of all, with three others (Dino Ferrari, Dome Zero, Jaguar E-type) following just behind. Most grids will feature at least one of these, which I'm calling the Fast Four.
Start the Lancia no higher than 3rd place at any track. The Dino, Dome, and Jag can be started as high as 2nd.
Start any Alpines, '63 Corvettes, either Mercedes 300SL, or Plymouth XNR Ghia as high as Pole position. These are almost as fast as the four mentioned above, and they make excellent pole choices.   
If none of the Fast Four show, remove 10 horsepower or more, especially If your vehicle has a lot of torque.
If NONE of the faster ones mentioned above show, remove up to 40 horsepower. Again, more should be removed from those which possess more torque than horsepower (such as the VW Beetle).  
Cars from 1979 or older are allowed, everybody else gets the day off. The concept of historic races has been with us since the days of GT2, and the Classic Sports Car Series is merely this concept's latest theme. 
This is another series which feels as though it has two distinct classes of cars to battle against: some fast, and some slow. WARNING: the slower class is really slow compared to the faster ones.  
Again, it seems PD has done rather a thorough job at making sure everyone is limited or boosted, but the cars below shine brighter than others.   
'78 Lancia Sratos
'71 Dino
'78 Dome Zero 
'61 Jaguar E-type
Others to watch are Alpines, the '63 Chevrolet Corvette, and the '54 Mercedes Benz 300SL Coupe or Chrome Line. These are faster because of some smaller advantages (the Alpine is ultra-light and nimble, the Benz has that rumbly V8, and so on).
Any cars not mentioned are nothing to worry about. This slower class of autos (Skylines, Fiats, even the '73 BMW 2002 or super-sleek '60 Plymouth XNR Ghia) will generally get passed as though they're standing still, unless power gets removed from what is recommended.   
Hard Sport Tires
Racing Suspension
Factory transmissions are usually best. Most cars from these will find themselves crippled for top-end if close gearing is installed. Full-custom gearing should be that last resort.  
Twin-Clutch Kit
Carbon Driveshaft for low-torque rear-drives
Limited-Slip Device if needed
ABS Brakes Off
'79 Honda Civic 1500 CS (1,600 pounds, ratios for 1,500 pounds were set logarithmically)
'66 Alfa Romeo Spider 1600 (2,000 pounds)
'73 Nissan Skyline 2000GT-R (2,900 pounds)  

GT Compact Car Championship
rating: *  
Autumn Ring Mini
(1,500) 17.44 -- 86 hp
(2,000) 20.91 -- 96 hp
(2,500) 22.93 -- 109 hp
(3,000) 24.00 -- 125 hp    
Cape Ring Inside
(1,500) 14.56 -- 103 hp
(2,000) 16.16 -- 110 hp
(2,500) 20.83 -- 120 hp
(3,000) 22.72 -- 132 hp     
Suzuka East
(1,500) 17.05 -- 84 hp
(2,000) 21.79 -- 92 hp
(2,500)  24.75 - 101 hp
(3,000) 28.04 -- 107 hp  
B-spec: +150 hp    
Note: this is a rather dull series  in need of some help. Starting certain cars on Pole and others on 2nd is recommended for the best GT Compact experience.
Start these cars on Pole
'09 Alfa Romeo MiTo
'13 Ford Focus ST170
'90 Honda CR-X SiR
any Honda Civic Type R
any Mini Cooper or Cooper S
'07 Peugeot 207
Start these cars on 2nd
any Mazda Roadster, Eunos Roadster, or MX-5
Toyota MR-S
Toyota MR2
If none of these appear on the grid, on 1st or 2nd place as shown above, remove 10 horsepower or more.  
When PD describes this series as a race for compacts, they weren't kidding. In my GT5 Racing Guide, I invented rules for car-length, so that only true compacts were allowed. Well in GT6, PD has implemented their own rule, which is really a nice touch. Cars can't be longer than 4.2 meters (4200 mm).
Once again, PD has screwed up their measurements, for those of us who have the North American version of the game! When looking at each car's length in the Settings menu, the measurement for length, width, and height are supposedly listed as inches. No, what is being shown are actually millimeters, not inches. This is a mistake they've been making on and off since GT2 days. So if a car's length says 3,395 inches, this is really 3,395 mm. 3,395 inches is equal to about 283 feet (85 meters).       
The GT Compact Car Championship is a  bit of a dud in my opinion. By this point in our GT6 careers we shouldn't be racing against the same faces, going back to power which was used at the beginning of the game, going back to cheap tires (and so on). All of these suggestions are being given to insert as much fun and drama into this series as possible. Keeping things edgy.     
The same cars seen during the Novice Hall make their grand (and final, let's hope) return. Renault Clio, Toyota Vitz, Honda Fit, and so on. It's hard to tell if they're packing more power than they did during the beginning of the game, since the overall PP rating goes back down to 450. But at least all three tracks are zippy ones to drive. Lots of turns, lots of drama.
Comfort Soft Radials
Racing Suspension, Hard or Soft (some won't need this)
Close-ratio Gearing with Twin Clutch Kit for many.
Cars Driven
'97 Suzuki Alto Works RS-Z (1,500 pounds)
'97 Suzuki Kei Works           (2,000 pounds)
'03 Scion xB                  (2,500 pounds)
'00 Volkswagen Beetle 2.0 (3,000 pounds  

Gran Turismo 6 Racing Guide