I have similar wheels and have made 4" spacers for the rear! From dimensions I've acquired online it appears 4" is about right for the wheels we have! When my car is finished my first order of buisness will be to replace them with extended a arms, I'm just not in the mood to back peddle at the moment! If they are wheel and hub centric they should work (within reason) for the rears, I would not go over an inch on the front!