im planning on getting a 3inch cat. However, most japan-made catback exhausts such as the 85mm piping hks hi power exhaust, use metric units. 85mm for example, is slightly larger than 3 inches. Assuming that most (if not all) catback exhausts are "bolt on", will slightly larger diameter catback exhausts connect to the cat without modification?

 

Yes, the piping is larger but the flange on the end is the same size.

 

i got this 3" cat-delet pipe it work out good for me with my cat-back exhaust system,check it out yourself http://cgi.ebay.com/ebaymotors/S13-S...mZ320020593232