Enter these codes on the name wheel. Once entered you can return to the wheel and input your proper name and the cheat will remain:
carnival - All Cars
drinkme - Small Cars
urco - UFO Selectable
sadist - Select Weapons in Game with Right Shift
tracker - All Tracks
changeling - Change Car During Mid-Race
makeitgood - Press [F6] for No Clipping, Press [F6] Twice for Flight Mode
tvtime - Enables [F5] and [F6] Cameras