Alternate Color
At the car select screen press Square.
Muscle Car
find 4 keys in any track; press down at gear selection screen.
Rocket Car
Find 8 more keys in the other tracks; press down at the gear selection screen.
City Bus
find all 16 keys; press down at gear selection screen.
Police Car
finish 1 player GP Mode then press down at gear selection screen.
Taxi Cab
finish 1 player Circut mode; press down at gear selection screen.
The UFO:
At the car selection screen, press and hold L1+L2+R1+R2 and then press X to select any car. Continue to hold L1+L2+R1+R2 on the tramission screen and release after pressing X. Quickly press and hold triangle until the game begins.
Mini-Truck:
At the car selection screen, press and hold L1 and press X to select any car. Continue to hold L1 throught the transmission screen until the race begins.
British Car
At the car selection screne, press and hold R1 while selection your car, press X to select any car, Continue to hold R2 through the tranmsission screen until the race begin