I would love as many JGTC cars to be included from over the years. GT2 had some old JGTC cars in, look at the R33's.
GT300
Mitsubishi FTO
Nissan Silvia
Nissan 350Z
Subaru Impreza all three versions
Toyota Trueno
Toyota MR2
Toyota MR-S
Toyota Celica old and new versions
ASL Gariya
Honda NSX
Mazda RX-7
GT500
Nissan R32 skyline
Nissan R33 skyline
Nissan R34 skyline V6 and inline 6 engined models, also old and current cars.
Honda NSX old and new
McLaren F1
Toyota Supra old and new
Mazda RX-7 ran for 1 or 2 years in the 90's in the GT500 class
Dodge Viper old and new
Lamborghin Diablo (it's a possibility)