The Self Righting Mechanism
Not sure how difficult it would be to implement, but it's a pretty simple idea. On many occasions in GMR I find myself accidentally flipping my car or being hit and end up flat on my roof. I find it slightly annoying that I have to kill myself and I'd like it if they add some sort of way to flip yourself back over so you can continue the race. I'd probably price it at around $1000.
I doubt that anything like this would be added, but it would be really awesome if it could be and it would definitely be a feature that separates it from other racer servers.
^ (Super accurate self righting mechanism)