I voted yes, but I won't be on GT5 for months, so yeah.
You're going to need to breakdown the car list more. GT1 changed a few times in the 90's/00's. The BMW McLaren and CLK are not in the same class as the Viper GTS-R or Corvette C5. I'd do something like this:
LMP
Audi R10
Puegeot 908 HDi
Audi R8
Pescorolo/Judd
BMW V12 LMR
GT1 - Late
Chevrolet Corvette C5-R (C5) ‘00
Dodge Viper GTS-R Team Oreca Race Car ‘00
Jaguar XJ200 LM Race Car
Chevrolet Camaro LM Race Car
Ford Ford GT LM Race Car
Ford Ford GT LM Race Car Spec II
Ford Ford GT LM Spec II Test Car
Honda NSX-R Prototype LM Race Car
Honda NSX-R Prototype LM Road Car
Honda S2000 LM Race Car
Mazda RX-7 LM Race Car
Mazda RX-8 Concept LM Race Car
Nissan 350Z Concept LM Race Car
Nissan Fairlady Z Concept LM Race Car
Nissan GT-R Concept LM Race Car
Pagani Zonda LM Race Car
Chevrolet Corvette Z06 (C6) RM ‘06 (600 hp limit)
Chevrolet Corvette ZR1 (C6) RM ‘09 (600 hp limit)
GT1 - Early
Mercedes-Benz CLK-GTR Race Car ‘98 (unfair?)
Panoz Esperante GTR-1 Race Car ‘98
BMW McLaren F1 GTR Race Car ‘97
GT2
BMW M3 GTR Race Car ‘01
Audi R8 LMS Race Car ‘09
Audi R8 LMS Race Car (Team PlayStation) ‘09