Various Cheats:
Pause the game then type one of the following codes for the desired cheat

matchthree - Get a super car 600mph
impact - Get unlim ammo (deathmath mode)
overkill - Get weapon mode in championship
likepamela - tuning phase 5 for all systems
clementine - Free choice in starting league
mccoy - Menus have animated switches
liselotte - All extra systems at 99
nalice - All cars
alloff - turn off cheats

Debug Cheats:
Pause the game and type in buggyboy to enable debug mode then press one of the following keys.

CPU drives your car A
Show frame rate F
Switch between cars G
Information system I
Screen capture P