Enter the following codes on the enter name screen:

CMCHUN: toggles gokart mode.
CMGARAGE: grants bonus car.
CMMICRO: toggles micro machines mode.
JHAMMO: enables all tracks.
PATSCREEM: enables TOCA showdown mirrored championship.
CMLOCK: Disable Tracks
TANK: Beep horn and shoot other cars
FLEXMOBILE: Rear wheel drive (better traction)
CMCOPTER: Helicopter view (one player mode only)
CMSTARS: Star light background
CMNOHITS: Disabale collisions
CMMICRO: Micro machines view
CMFOLLOW: Film camera view (one player only-camera changes in demonstration mode)
CMLOGRAV: Low Gravity
CMTOON: Toon background
CMRAINUP: Reverse rain
CMCATDOG: Rains frogs
CMMAYHEM: Agressive opponents
CMDISCO: Disco Fog (3DFX only)
CMHANDY: Larger hands for in car view
CMIMPOSS: Expert Mode
CODIES & GONGOGO : Unknown