When starting the game and you must choose which car you would like to 
buy, select the Mazda RX-8. It is the fastest in stock out of all the 
other cars.

When starting at the beginning of the game, the Mazda RX-8 may be the 
fastest out of all for you to use, but it depends on your driving. Also 
try the Toyota Corolla GTS or Nissan 200SX.

For League 7 cars, the Infiniti G35, Lexus IS300 and Nissan R32 and R34 
are recommended. The Lexus IS300 is good for the Drift Obliterator, Drift 
King, and Pink Slip races. The Infiniti G35 is good for unlocking 
performance mods. The Nissan R32 and R34 are good with the circuit racing 
and drift racing throughout the entire game.

For easy wins, always get cars that have the max class of the class that 
you are in. Prototype mods are always available (if you unlocked them). 
For example, if you are in Class 1, buy a car that has a max class of 1. 
It most likely win the race.