You know, I just couldn't see paying Mufflex for their 3.5" catback, so I built my own! Nothing to it at all; a few feet of 3.5" tubing, one 60* angle up to a 90* down to a 90* over to the muffler, and one more 90* out the back. I built the whole thing for $180, including a Dynomax round 21" race "muffler". It took about three hours total on my driveway with a little 110v welder, and it came out great.

I only wish it wasn't so damned loud! If I wind up driving this car at all there's a good chance I'll put a fluted muffler in right at the front of the I pipe that can be removed.

How many of you guys have built your own? If there's some interest in this, I'll get some pictures one of these days. Right now my car isn't running due to an issue with the DFI, but hopefully that will go away soon.

 

I've yet to make a 3.5" system but, I've made 5 3rdgen systems including this one I made this for a friends v6 camaro...



It's 2¼" y-pipe to a 2¾" I-pipe...