Hi Bob,
Sorry just got round to seeing your message, sorry.
Yes the BBS wheels do fit the car and the arches with no fouling, on road or track. They were very close (3mm) in the springs at the front, but I was assured by Eric Gissler at BBS GmbH that they would fit and they did. They do make different offsets for GT3 and RS though. Would you need the GT3 size with the GTS? Tyres are GT3 stock.
Pete