At the main menu, type "icancheat" and use the following codes at the indicated screen and press [Enter] to activate them:
No clipping mode (Main menu): clipped
Reckless mode (Main menu): reckless
Set number of laps (Track selection): lapset
Cloverleaf and Pepsi Planet tracks (Track selection): freeride
Expert mode (Car selection): takemeon
Xwave car (Car selection): widebodyopen
Wraith car (Car selection): wildone