All the Premium Lexus SC430, Honda NSX, Chevrolet Impala, and Nissan GT-R are all basically the same cars, with identical stats, but counted as separate cars because they are painted differently. They obviously did this so they could say there are more premium cars in the game. Personally I think this is shocking behavior, and may even be illegal under false advertising laws. If this is legal, then surely it would also be legal to count each colour X1 as a separate car, and same with all the other cars, and then claim that there are 1000's of premium cars in the game. It would obviously be illegal. I feel PD are on dodgy legal ground here.
Look closer at the cars. There's actually small differences between them.
For example the NSX race cars, the ARTA and the green one (takata?) are actually faster, and there's small differences in their performance and handling.
The same goes for the GT-R race cars. Some even run with a weight penalty I think (50kg), and despite that they're still competitive. Again, there's small differences in the handling and acceleration, weight distribution, etc.
Not too sure about the Lexii (Lexuses?). Got the Petronas TOMS 430, like the look but not the drive so I never bothered with the rest (uglier versions if you ask me). But again there's probably small differences.
There might not me much in it, but you're implying there's so little in it that neither team would mind if you swapped out their cars between them.
The ratings may just be there to keep those teams happy. If you saw that one of the GT-R teams had a 10hp advantage or something and you were from another team, you'd be angry because you know that not as many people would use your car.
But since the people who know about (SuperGT) know that such and such team is faster, or hve their favorite car/driver, then they're not going to buy based on the numbers, like a large amount probably would.
As fas as I know, they're not counting each 'colour' of the X1 (or any premium car) as a different car. The F10's are in fact counted as the same car, despite Alonso's being obviously the better car
The Carbon X1 for instance, has different performance, I think it's a bit faster than the others?
The closest thing you'd get is the Audi R8 and the R8 V10. One COULD almost argue that the V10 is an option, but it's closer to a trim package or similar, like the difference between a v6 mustang convertible (girls car) and a V8 Mustang GT (bearded girls car).