If I had one, I'd be taking the original tyres off and keeping them in storage. They are part of the cars provenance. I saw an RS1600i at a show a few years ago, and he had a set of wheels with the original Dunlop D4 tyres just for show purposes. I see the CS S been similar to the RS1600i, so even if you don't plan on keeping the car, you will be doing your bit to help owners down the line who might want to pamper it.