Type in TOPDOWN as your name. 
You'll hear Tiff say "Cheat Mode Enabled" and you'll have a GTA type view 
available to you. 
You can also try these as names: 
HANGOVER - Makes Things go a Little Hazy.
REPEL - Unknown Effect.
DOUBLE - All Tracks
CARTASTIC - All Cars
OUCH - Battle Mode
RUBBER - Bouncy Crashes
MOVIE - Silly Crashes
HIGHJUMP - Low Gravity
HANGOVER - Blurred Horizon
SKINNY - Wheels Only View
SKATES - Double Speed, Brake, and Grip
GIRDLE - Higher Decors and Walls, Side of Road Higher, Narrower Roads and 
Shortcomings Amplified
TIMEOUT - Full Championship Distances
ECKLOCK - Unlock Extra Track
FASTBOY - Turbo On
MINICARS - Micro Machines Mode
TRIPPY - Psychedelic Mode