Before starting a rally, you are given the option to set-up your car, and if necessary, repair the damage you may have inflicted.
Parts of the car that may be tweaked or are prone to damage are:
Suspension Brakes Engine Gear Ratios
Electrics Steering Tyres Handling
You are allotted a certain amount of time to perform these Set-up and Repair operations - this may lead to you having to prioritise the essential with the non essential tasks!