To make your car the fastest then you will have to buy every top performance part and set:
Transmission-a ll top speed
Brakes-all front bias
Turbo/Supercharger-a ll high RPM
Tires-in the middle
To get your car really fast then put all these performance parts to that setting and enjoy the fastest car! The porsche carrera GT, lamborghini murcielago and mercedes-benz SLR maclaren all go 282 MPH with nitrous on at the same time!
Infinite Nitrous cheat: left, up, left, down, left, down, right, x