Unlock All Cars
Press start button, Left, Up, R2, L3, Right, X, Circle, L1.

Infinite Nitrous
Left, Up, Left, Down, Left, Down, Right, Square.

Castrol Cash 
At the main menu, press down up left down right up square triangle. This gives you 10, 000 extra cash.

Extra Money
Press Right, Up, Down, Up, Down, Left, Right, Square at the main menu.

Unlimited Speedbreaker
Press Down, Right(2), Left, Right, Up, Down, Square at the title screen.

Easy Money
Press Up, Down, Left, Down, Right, Up, Square, Triangle.

Cheat Code Entering
To enter cheat codes, you have found, just input them on the main menu. (Not where you press start). It's the menu where it has career and challenge series and other stuff.

Extra Money 
At the title screen, press Down, Up, Left, Down, Right, Up, Square, Triangle to get an extra $10,000 in Career mode. If you entered the code correctly, a message will appear. Note: This code can only be used once.

Special Car "Cardboard Box And Driver" Vinyl Unlock
Need For Speed Carbon Special Logo Vinyl Unlocked; up, up, down, down, down, down, up, square

Infinite Speed Breaker
Down, Rigtht, Right, Left, Right, Up, Down, square.

Unlock All Vinyls
Down, up, right, left, R1, L1.

Need For Speed Carbon Vinyl
Press Right, Up, Down, Up, Down, Left, Right, Square at the main menu.

Digimon: Digital Monsters Plymouth Hemi Cuda
Enter: Up, Left, Down, Right(2), Square(2), Circle (2), Triangle, Square, At the Title Screen.

Special Car NFS Carbon Logo Vinyl Unlock
Need For Speed Carbon Special Logo Vinyl Unlocked; right, up, down, left, right, square

Unlimited Crew Change
Press Down, Up(2), Right, Left(2), Right, Square at the title screen.

How To Get Kenji's Mazda Rx7
After beating him in both the city race and the canyon duel. A set of 6 reward cards will appear, pick the second or third card to get the pink slip to his car. Then when you go back to your safe house his car will be in your garage.

Easy Money
Once you have completed Career mode, set Samson as your wingman with Neville also in your crew. You can repeat any races you have already completed in which a wingman is used and recieve $750 for each race completed instead of the $500 without. This can also be used on first time races for maximum cash output.

Rosewood District?
Sometimes, when you hear the dispatcher for the police, you might hear Rosewood District (in Rockport in NFS MW).

How To Get Angie's Charger
After beating her in both the city race and the canyon duel. A set of 6 reward cards will appear, pick the first card to get the pink slip to her car. Then when you go back to your safe house her car will be in your garage. Your welcome!!

Getting Territory
You only have to win two races in each section of enemy owned territory to take it.

Moving Floor
At the car dealership when you are looking at cars if you click R2 to veiw the car the car will stop moving, but the floor will keep moving in a circle around the car.

AUDI Le Mans Quattro
To unlock the AUDI Le Mans Quattro you have to beat Darius in the Canyon Duel.

Collectors Edition Cars
Successfully complete the indicated event(s) in the Challenge Series to unlock the corresponding car:
Aston Martin DB9 (Exotic): Defeat Wolf in Boss Battle mode.
Dodge Charger RT Classic (Muscle): Defeat the 21st Muscle Car Gang.
Jaguar XK 2007 (Exotic): Successfully complete all three Turf War races.
Mazda RX7 (Tuner): Defeat Kenji in Boss Battle mode.
Nissan 240SX (Tuner): Successfully complete all three Checkpoint challenges.

Easier Speedtrap Races
Activate your Blocker/Brawler before the race. While racing and coming up towards a speed trap, stop your Blocker/Brawler. Your Blocker/Brawler will stop, crash the other car(s), and drastically slow down their time. Remember that the peak Blocker/Brawler moment is just before the speed trap.

More Money
If you have a previous NFS: Most Wanted (but not the Black Edition) save on your memory card you get a bonus $10,000 when you start a career in career mode.

Unlocking Crew Members
You need a crew to help you out, but you have to do things to get their attention.
Sal: Complete 4-6 races
Yumi: Defeat Kenji
Colin: Defeat Wolf
Sampson: Defeat Angie
Yumi: (Scout) Beat Bushido
Nikki: (Drafter) Beat all three "gangs"
Neville: (Blocker) Start of game
Sal: (Scout) Complete 4-6 races