bottle caps are not 15" wheels guys.
In any case:
the insurance company has probably already taken photos of your car with the RS on them, so its possibly too late, and "frauding" them they wont take to kindly to that. if you are going to take the wheels, you might as well take the stereo, the steering wheel, the seats…. where does the list end.
I suggest you let them take the car, have them pay out, and tell them that you want first option to buy the car back.
Insurance companies are not an entity you f**k round with, because you will never get insurance again etc. Thats why you have insurance in the first place