Hi just a quick question what diameter is the pipe coming out of the MY00 prodrive backbox and what size is the tailpipe. thanks in advance.

 

New age pipe comes out of box at 4" OD for all the tail pipe, the inside is perforated with a thin sound reducing wall that reduces the ID. I think only difference on the classic is a different front bracket. Inlet is 2.5" at front of box.