Cars

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.