1999 Mitsubishi Eclipse Gs-t In Arcade Mode
Press Up, Down, Left, Right at the main menu to enter the code entry screen. Then, enter IGOTGST as a code

Mazda Rx-8 In Arcade Mode
Press Up, Down, Left, Right at the main menu to enter the code entry screen. Then, enter RENESIS as a code

Police Warning Instead Of Ticket
Press Up, Down, Left, Right at the main menu to enter the code entry screen. Then, enter LETMEGO as a code. The first three times you are pulled over in street mode, you will be released with a warning

Various Codes
To enter these codes press UP, DOWN, LEFT, RIGHT at the main menu. This will take you to a cheat console where you can enter these codes:

Police car: GOTPOPO
1996 Toyota Supra RZ: SICKJZA
2004 Toyota Celica GT-S Action Package: MYTCGTS
Free car repair: FIXITUP
Pac-Man vinyl: GORETRO