8 cars
3 fully tuned:
Toyota Yaris 1,5L : my first car
Honda S2000: one of my favourites
Nissan Skyline GRS V-spec II: I'm really dissapointed with this car, it goes fast as hell but it doesn't turn
Then I have some won cars, with only 1 good one: Subaru Impreza WRX
Only have 10, but I'm not that far into the game. The Subura Wagon and Opel Speedster are my 2 favorite. But I also have a Mazda Miata, VW Bug, and Toyota Viti tuned out to the maxes.