is it possible to manually change anything to make 1. pershon shooter while in car?
Good luck, best I've seen is playing around with the "birdseyeview" console command, I don't remember it offhand since I haven't played rage in a couple months but I do know that you can zoom in/out quite a bit, you MIGHT be able to zoom in with it to get a pseudo-1st person mode, though I'd guess you would probably not see your vehicle model.
Search for "Rage vehicle birds eye view" should be some stuff on the steam powered forums