Here are some:

REMOVE     Remove cheat codes
[blank]    B&W mode
CINEMA     Wide Screen Mode
LOVEBUN    Secret car
MAYTE      "
TINKLE     "
SUICYCO    "
2X4B523P   "
FORMULA1   "
SUPERMAN   destruction mode
DR DEATH   invincible human cars
GOLDBOY    premier cup
MREPRISE   bonus cup
CUP WON    see end sequence
I WON      see race win
ROLL EM    see credits
DUEL       killer opponent
TOPTUNES   alternative sounds

enter them as your name in the config menu

enjoy!

Todd