Tbh theres tonnes of cars around that area.
MP4 McLaren, Ferrari Scuderia, R8, GTR, Gallardo, The other insane Lambo that I cant spell. Ferrari Italia, Merc SLS, Merc SLR, Lexus LFA
All are incredible, it depends on your driving style. I just tuned up an R8, its pretty epic. First two races online I got 1st and 2nd on Grand Valley.
Scuderia vs MP4 on the Nurb online was epic too. I wouldn't rule any of them out. Everyone seems to go for a GTR, myself included. Wasnt the first I got though.