I haven't been driving it that much for the last 3 years since I got my Cayman, probably less than 1,000 miles, but lately I have been driving it again. The Cayman is fully set up for track and so is a hassle for street driving, but the Boxster is perfect for that. Not to leave well enough alone however, I am putting track goodies on the Boxster and getting ready to take the Boxster to Sebring with Suncoast PCA 4/30-5/1
In this picture I was test fitting my Apex SM-10 wheels (front 18x8.5 ET 42, rear 18x10 ET 36) with Continental ExtremeContact Force, 245/35/18 and 275/35/18. The backs look like they stick out pretty far but no rubbing, at least at stock height. This is the set I have been running most recently on the Cayman and they seem to fit wheel on the Boxster, front diamter is close to 25" and the back isn't that much higher than the stock 18" fitment diameter.