Parts
Enter these codes at the Press Start screen to unlock level 1 & 2 performance and visual parts. A sound will confirm that you entered the correct code. Cheat Effect
L, R, L, R, Left(2), Right, Up Level 1 Performance Parts
R(2), L, R, Left, Right, Up, Down Level 2 Performance Parts
R(2), Up, Down, L(2), Up, Down Level 1 Visual Parts
L, R, Up, Down, L, Up(2), Down Level 2 Visual Parts

Earn cash and unlock vinyls
Enter the codes at the start menu. You can only input the money codes once, and only one vinyl code at a time. Cheat Effect
Left, Left, Right, X, X, Right, L, R Earn $1,000 in career mode
Up, Up, Up, Left, R, R, R, Down Earn $200 in career mode
Up, Up, Up, Up, Down, Up, Up, Left Unlock Burger King vinyl
Up, Down, Up, Down, Down, Up, Right, Left Unlock Best Buy vinyl

Unlock Cars
At the Main Menu,when it says Press Start,enter this cheat. Cheat Effect
Up,Left,Up,Up,Down,Left,Down,Left Unlock Hummer H2 Capone

Sponsor Cars
The publishers secretly allowed players to drive the cars of celebrities who worked on the game's music. Enter these code at the "Press Start" screen. (note, use the + pad not the D stick)
After entering the code, go the the car selection screen (quick race, split screen...) and press R until you get the "SPONSOR CARS" option. Cheat Effect
Up, Right, Up(2), Down, Right, Down, Right Chingy Navigator
Up, Left, Up(2), Down, Left, Down, Left Capone H2 Hummer
Up, Down, Right, Up, Left, Down, Right(2) D3 GTO
Press Up, Down, Left, Up, Left, Up, Right, Left ShineStreet Lexus IS300

Okay I have just found out how to do this cool glitch. First you must unlock the split hoods option. Then go to the split hoods option. When scrolling down looking at the hoods open press down or up and x at the same time. This may take some practice at first. If you did it correctly, the hood will open inproperly. To ensure that you did it right press x again and the hood will normally close going to it's origianal spot. I will tell you this glitch will do nothing to your game. Its just for fun.

Catch ya later

Burger King Vinyl
Up(4), Down, Up(2), Left.

Best Buy Vinyl
Up, Down, Up, Down(2), Up, Right, Left.