[rdass623]

in your original post, you did not specify oem 18 wheels, and not all Porsche wheels have the same offset. for the 18s I have on my 987, I need 25mm spacers for the rear clearance. aside from that, the only way to be sure of fitment is to measure the wheel lip or the fattest part of the tire for clearance. once you get your measurement, just multiply the number of inches by 25 and you will get the size converted from inches to mm. if you come out with a measurement like 23 mm, opt for a 20 mm spacer rather than a 25 to avoid the possibility of interference