GEARSHIFTERS

You purchase upgrades via the 'Car Setup' screen using in-game credits collected from defeated enemies and as rewards for deliveries. You'll also have to collect the 'Schematics' that are dropped in order to unlock certain things. You should be able to buy everything some time after the main campaign through normal gameplay, however you can speed up the progress by buying the extra credit boosters and upgrades early on. This does include all the weapons, charges, tyres, extras and combat parts before it will unlock.