Tokyo Xtreme Racer: Zero Cheats
While choosing your transmission (AT or MA) hold R2 + X + Circle, and hold it until the loading screen ends and the game begins. There will be a Genki ornament hanging from the roof, go into first person view to see it.
Blue Mosquito Ornament
Do the same as above except enter L2 + X + Circle.
Same as above except hold L1 + X + Circle.
Same as above except hold R1 + X + Circle.