Originally Posted by Stainless Works

Since all mufflers are made at our facility, we control the level of sound and flow for each muffler design. Keep in mind its nearly impossible to have hi-flow with minimal noise. Our 3" S-Tube design muffler has found its way on many cars with 1000+ HP. Typically 4" mufflers are found on high compression diesel applications or Race Only applications. The straight through design mufflers will allow some of the turbo sounds to leak out a bit more, for reference check out our new Eco-Boost exhaust with a single 3.5" S-Tube muffler, you can definitely here the turbo with this design.

Watch Eco-Boost Video

Originally Posted by 05GMC4.8

Single 3.5" s-tube according to his post

Originally Posted by Jetn3

Do you have a sound clip of this? Would love to hear what a 4" mbrp sounds our turbo gas trucks.

Originally Posted by lglowe

I'm running a full 4in from turbo to dump and it sounds pretty good at wot to me from outside of the truck. It's some kind of diesel muffler that is straight through and the inside looks kinda like a cheese shredder lol. It's reversible but I have it so the "scoops" in the muffler point down stream and don't grab the air if that makes sense. I can post a wot fly by video if anyone wants