SKYLINE GT-R M¡¦spec(R34,J)
Mazda MX-5(J)roadster_89_opt
Mazda MX-5(J)roadster_sr_lmt_97_opt
Mazda MX-5(J)roadster_sspl_96
HONDA S2000_e_99
HONDA S2000_e_99_ext
Viper GTS-R Team Oreca_00 (Chrysler)
I think that's it, with the exception of the sample cars. I may be wrong about the S2000s, but I don't think they can be gotten in the game anywhere.