Carmageddon - Full Version
Cheat Codes

BIGBOTTOM - Bodywork Trashed
SUPERHOOPS - Explosive Peds
IGLOOFUN - Hot Rod
GOGGLEPLEX - Underwater Ability
SPAMFORREST - Instant Handbrake
INTHELOFT - Drugs
BUYOURNEXTGAME - Jelly Suspension
CHICKENFODDER - Bouncey
FUNNYJAM - Turbo Peds
TRAMSARESUPER - Pedestrian Harvest
ISLANDRULES - Vesuvian Corpses
SMALLUDDERS - Giant Peds
SPAMFRITTERS - Free Repairs
GIVEMELARD - Mega Bonus (Loads Of Money)
SPAMSPAMSPAMSPAM - Pedestrians Glues To Ground
HAVESOMESPAM - Gravity Has Gone Strange
MOOSEONTHELOOSE - Pinball Mode
ILOVENOBBY - Pedestrains Shown On Map
RUSSFORMARIO - Pedestrian Electro Bastard Ray
HAMSTERSEX - Blind Pedestrians
NAUGHTYTORTY - Pedestrian Respawn
BOYSFROMTHEBUSH - Grip O Matic Tires

At the Network Race-type selection screen, type in:

JOYRIDER

You'll get access to all cars for network play. You'll need to select 'all' cars in the options screen to use them.

NOTE: This works with manual or random car selection.