At the "Press Enter" screen press the following to activate any of
the current cheats:

regmebaby - Gives you 20,000 in career mode to start
opendoors - Access to whole driving world
ordermybaby - Access to all cars
gimmevisual1 - Unlocks Visual Upgrades Tier 1
gimmevisual2 - Unlock Visual Upgrades Tier 2
needperformance1 - Unlocks Performance Upgrades Tier 1
needperformance2 - Unlocks Performance Upgrades Tier 2
goforoldspice - Unlocks Old Spice Vinyl
needmybestbuy - Unlocks Best Buy Vinyl
gotmycingular - Unlocks Cingular Sponsor Vinyl
gottahavebk - Unlocks Burger King Vinyl
gottaedge - Unlocks Edge Sponsor Vinyl
davidchoeart - Unknown
shinestreetbright - Unknown
wantmyd3 - Unknown
wannacapone - Unknown
gimmechingy - Unknown
yodogg - Unknown
tunejapantuning - Unknown

IMPORTANT: Not all cheats works in Career mode