Need for Speed: Undercover Cheats PS3 Cheats,

Challenge Series Cars (DLC Content):
Battle Machine RX-7 - Finish the first 30 Challenge Series Events.
Speed Machine 911GT2 - Finish all 60 Challenge Series Events
Dominator Corvette Z06 - Dominate over 30 Challenges Series Events.

Even More Cars
At the in-game cheats menu:
Die-Cast Audi R8 car - Enter "9:G3IF or "9;&4)%
Die-Cast BMW M3 E92 car - Enter )B7@B=
Die-Cast Dodge Viper SRT10 car - Enter !C6;C>E or ""6<"?$
Die-Cast Lexus IS F car - Enter !7I3JMI or !8(4*-(
Die-Cast Nissan 240SX (S13) car - Enter ?P:COL (that's the letter "O") or @/;#/+
Die-Cast Nissan GT-R (R35) Police Version car - Enter yp}jwa or "90=*6@

More Cars
At the in-game cheats menu:

citwoxq53f - Chevrolet Camaro Concept
qlcukc4bqm - Dodge Charger (1969)
i3kxodepfc - Ford Mustang GT
2d5dviyrlgn - Pontiac GTO (1965)
>8P:I; - Porsche 911 Turbo
NeedForSpeedShelbyTerlingua - Shelby Terlingua

Cars and Money
At the in-game cheats menu enter these:

%%$3/" - $10,000 in-game
0;5M2; - Lexus IS F
-KJ3=E - Lotus Elise
?P:COL - Nissan 240SX
!2ODBJ: - Volkswagen R32
S1D3K1CK - $15,000 in-game