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ST ones do Mate, and I'd guess RS do too as the PCD is probably the same. Why not take it round to the bloke with the wheels and try one on. I've got 215/17/ 45 tyres on 17 inch alloys which are pretty wide, and they fit under the standard arches OK with no rubbing. I have an ST wheel/tyre as a spare.
RS are 18", the offset etc will almost certainly be different and the wheels will look totally odd I should think as they will stick out from the arches, whereas the RS has the arches to accommodate this.