they will have the wrong PCD (bolt diameter) so you'll need adapters. Porsche wheels generally have offsets high enough to fit adapters, but be aware of the widths of the rear wheels - you might be alright with the rears from narrow-body cars (Boxster/Cayman, 911 C2/C2S) but the rears on wide-body cars (C4/C4S/Turbo/997 Targa) will be too wide to fit
best thing is to find the wheels you want and then ask the specific question for those wheels with the width/offset
