Hot Wheels Highway 35 World Race Cheats

Every tracks:
In the "Press Start" screen, push R2, L2, Circle(2), Square(2) 

Every cars:
In the "Press Start" screen, push  R2, L2, Square(2), Circle(2)
User Cheat by Dancing_Ghost

Kurt's Spy Car:
In the "Press Start" screen, push Square(2), Triangle, Circle, X  

Bonus vehicles:
Submit the code SMASHMOUTH to unlock the "SuperTuned" and the "SlingShot" vehicles.