I had my exhaust shop make me an ORP using a 16" Dynomax bullet muffler. They put a flange before and after it, so that I can swap the cat in and out. It's acutally quieter with the ORP in it than with the cat. It sounds really good. I had an ORP with just a straight pipe, and it was LOUD. Best of all, the bullet ORP gets rid of most of the raspiness that was there without the bullet muffler.

 

I thought about doing that. I hated how the car sounded when I went to the ORP. It was great at idle but I hated the raspiness when your on and off the gas. I've got SLP single cats, ORP, Borla. I went with a vortex cone at the end of the ORP, it made it sound much better but I think the cone is a little more restrictive than a bullet would be. I might try that.

 

I did the same thing with the Borla XR-1 shorties.... a 3" CarSound cat in each branch of a 3" Y-pipe, and flanges on the cats and the Borlas so they could be swapped out for running leaded fuel at the track. With a Mufflex 4" catback, the car had a really deep, rumbling exhuast that would put a throb in your chest at about 2,500rpm. And the cats were LOUDER than the Borlas, also.