Change the size:
 
At the "select car" screen press and hold up
c, & press down c, release & press & hold down
c, & press up c to change the size of the car.

Submitted by a2000sktr@aol.com 


Enable Foggy Night:

At the options screen during gameplay select 
'extreme fog' with all four C buttons held 
down. This will give gamers the impression of 
playing through races at night. 

Change Fog Color:

At the car select screen hold Z and press 
C-Down, C-Down, C-Down. 

by unknown