Stupid additions I would like to see:
Fully animated Playboy bunny pitcrew (realistic physics effects please)
Fully simulated windscreen washer system
Spinner mags (if someones already made them: you are a pikey)
The ability to undo the safety harness and be thrown around the cabin/out of windshield edit: better yet, unharnessed backseat passengers for a 24hour endurance version of 'corners' WITH realistically modeled vomiting.
Rocket powered vehicles (WITH afterburners)
To be able to jump out of my wrecked vehicle, shake my fist and throw my helmet at passing cars