This is a great cheat which will unlock ALL the bonuses in the game without you having to spend hours unlocking them individually. Just go to the 'Options' screen and select 'Cheats' and enter the password 'fullyloaded' without the quotes.

Enter the following cheats by going to the 'Options' menu and then 'Cheat Codes'.

Unlock Max Nitro:
Fillmeup

Unlock Atlanta & Detroit:
Roadtrip

Unlock ALL cities in Arcade mode:
Crosscountry

Unlock Vechicles take NO Damage:
Ontheroad

Unlock Special Agro:
Dfens

Unlock Special Zone:
Allin

Unlock Bunny Ears:
Getheadl

Unlock Pumpkin Head:
Getheadk

Unlock Skull Head:
Getheadn

Unlock Snowman Head:
Getheadm

Unlock Yellow smile:
Getheadj


Cruise Mode Unlockables

Flag Vinyls:
Find 12 Rockstar logos in Cruise mode

Rockstar License Plates:
Find 24 Rockstar logos in Cruise Mode

Race Starters as Riders:
Find 36 Rockstar logos in Cruise Mode


Career Mode Unlockables

Unlock Car Rims Set 1:
Beat Carlos in 3 of 3 Races in San Diego

Unlock Car Rims Set 4:
Beat Lamont in 3 of 3 Races in Atlanta

Unlock Car Rims Set 5:
Beat Roy in 3 of 3 Races in Detriot

Unlock Car Rims Set 6:
Beat Caesar in 3 of 3 Races in Detriot

Unlock Car Rims Set 7:
Beat Caesar II in 3 of 3 Races in Detriot

Unlock Sportbike Rims:
Beat Vito in 3 of 3 Races in Atlanta

Unlock Chopper Rims:
Beat Naomi in 3 of 3 Races in Atlanta


Unlockables

Unlock Cadillac Sixteen:
Get 100% Completion

Unlock Nissan Skyline:
Beat all 13 tuner race tournaments

Unlock Skully:
Beat all the races for the 'Choppers of America Bike club'

Unlock Cadillac Escalade ext:
Win the second San Diego tournament

Unlock Cadillac Escalade ext Dub Edition + $10,000:
Win 'Hotlanta Tournament' in Atlanta

Unlock Chrysler 300c Dub Edition:
Win 'Balboa Park' tournament in San Diego

Unlock 68 corvette:
Win all the 'Muscle Cars of America' races

Unlock El Diablo Rigid:
Beat Vanessa three times in 'Career' mode

Unlock Hotmatch Cuevito Motorcycle:
Win all of Phil's four races in 'Career' mode

Unlock Lexus 1300:
Complete all of Vanessa's 1st four Races in 'Career' mode

Unlock Four-Twelve:
Complete all 16 Exotic Races

Unlock Lambougini Mercialago:
Complete 'U.S. Champs Series' (After Beating Detroit)

Unlock Cadillac CIEN:
Beat the second tournament in Detroit

Unlock Ninja ZX 12R:
Win all the sport bike races

Unlock G55 Amg:
Win all the truck races