All you have to do is beat the first championship Grand prix, then go to faceoff mode (under special) and beat it then you can use it.
Get Face Off Mode
Finish championship mode in one time.
Quick Start
To get a quick start, press the accelerator when the one is fading away.
Go the wrong way with no traffic.
Select the Interstate as your course, then right after the start there is a big freeway go over to the far left lane and start going as close as you can to the wall, there will be little gaps in the barrier that you can slip through.
Extra Tracks
Beat the first championship race in first and you get Hillside east, Twilight Harbor and Gridlock, Usa.
Extra cars
To get the Roadster,Tow Truck,Saloon GT, and the Bus you must complete the 4 grand prix. Then go to face off in special and beat the car and it will be one of your playable cars.
Get free Run Mode
Finish the game in one time.
Get Bus
Beat the bus in Face off 4.
Get Saloon GT
Beat the Saloon in Face off 3.
Get Towtruck
Beat the towtruck in Face off 2.
Get Face Off Mode
Finish championship mode 1 time.
Survival Strategies
Use the Roadater or the Supermini. The Roadster has the best handling, and the Supermini is the smallest. Race the course in Free Run to learn it inside and out. Race cautiously, but not slowly. Try to eliminate all outside distractions.