I have a 98 GT, and I have flowmaster 40 series, that are 2 1/4 in inlet and outlet. I am probably going to order a Mac Prochamber H-Pipe 2 1/2 in. Would a muffler shop have any problem installing the H-pipe, couldn't they just use flanges? Also I was wondering if by going from 2 1/2 H-Pipe to a 2 1/4 in. Mufflers and tips, would that hurt performance or sound noticeably, or would it be way to small to not even bother getting new mufflers and tips?
Shouldn't hurt performance either. If you had a 2.5 cat-back it prob would only give you a few more hp at best. I have a magnaflow x w/cats going into the stock 2.25 pipe with Borla's welded in. Sounds great and gave a excellent SOTP gain. Good choice with the Prochamber it sounds amazing with flows. Are you doing the install yourself?
