Hold R1 while selecting a transmission type. Keep the R1 held through out the loading screen to see a man hanging from the roof of your car in first person view.
Change Horn to Siren
Select rear spoiler type 5 for R30 and R30M, to change the horn to siren.
Clean Pause Screen
When Pausing, press triangle + square to remove the Pause menu. You can't unpause the game while removing the pause menu. Press TRIANGLE + SQUARE to show the Pause menu.
Get a Special Nickname
Put a team sticker on the car you were driving for this team to get a special nickname.
Manipulate Parts Camera
In Parts type select screen, selecting Aero parts or exhaust will make the camera move toward the car, but pressing triangle button will not cause the camera to move close to the parts (you'll see the entire car on your screen). Press triangle button again to see the close-up.
Race through the air
After defeating a rival, let the game go into autopilot mode. When in this mode, open the CD tray and watch the screen. Eventually everything will disappear except the cars, traffic, and background image. It will appear that the car is racing through the air.
Skyline car
Defeat the Speed King to get $3 million and unlock the Skyline car for purchase.
Wanderer Requirement
To be able to racer wanderer #370 your car must be equipped with the stock engine.
Wanderers Requirements
While not exactly a cheat, this will allow you to race some of the wanderers that you may have missed in order to unlock the final racer.
Rival 316 Will appear when days are a multple of 7, you must have a shindowa plate
#319 you must have an import car and 180 days must have passed
#326 FF type car needed, days must be a multiple of 10
#328 6 cars needed in garage
#329 will appears between 9-11pm
#330 shonan plate needed, days must be a multiple of 7
#331 will appear between 2-4am
#334 must have under 30mi. on odo.
#338 first two numbers in days total must equal four (ex. 220days) and you must be using a two seater
#340 odo. must have 2000+ mi.
#341 must have 25 cars in garage
#342 odo. must have 120mi. or less and you need to use the stock exhast.