Disney XD car:
Select the "Options" tab at the main menu. Then, press X, Down, X, Down, X,
Down. The Disney XD car will now be available in the garage in Quick Play mode.

AMX Coyote:
Select the "Options" tab at the main menu. Then, press Left, X, Left, X, Left,
X, Left, X, Left, X, Left, X, Right. The AMX Coyote car will now be available in
the garage in Quick Play mode.

Computer Spiele car:
Select the "Options" tab at the main menu. Then, press X, Up, X, Up, X, Up. The
Computer Spiele car will now be available in the garage in Quick Play mode.