Enter these codes at the title screen:

Need For Speed Undeground 2
$1000 in career. RX-8 and Skyline in Quick Race
Left, Left, Right, Square, Square, Right, L1, R1

Unlocks the Best Buy car Vinyl
Up, Down, Up, Down, Down, Up, Right, Left

$200 in career
Up,Up,Up,Left,R1,R1,R1,Down

Unlocks A Hummer H2 Capone
Up, Left, Up, Up, Down, Left, Down, Left

Unlock All Bonuses
L2, R2, L1, R1, Up, Down, Right, Left

All Circuit Tracks
Down, R1, R1, R1, R2, R2, R2, Square

Burger King vinyl
Up Up Up Up Down Up Up Left

Need For Speed Undeground 2 Upgrade Codes
Enter the following cheat codes at the start screen:

Unlock Visual Level
1 R1, R1, Up, Down, L1, L1, Up, Down

Unlock Performance Level 2
R1, R1, L1, R1, Left, Right, Up, Down

Unlock Performance Level 1
L1, R1, L1, R1, Left, Left, Right, Up

Unlock Visual Level 2
L1, R1, Up, Down, L1, Up, Up, Down