All races:
     Enter MATTL66 as a code.

All cars:
     Enter YAYCARS as a code.

All tracks and mini-games:
     Enter IF900HP as a code.

Maters Speedy Circuit and Maters Countdown cleanup:
     Enter TRGTEXC as a code.

Super fast start:
     Enter IMSPEED as a code.

Unlimited boost:
     Enter VROOOOM as a code.

All paint jobs:
     Enter R4MONE as a code.

All movies:
     Enter WATCHIT as a code.

All concept art:
     Enter CONC3PT as a code.