Mine is fairly quiet with a large Magnaflow muffler and a 4" diesel cat, but it's all subjective. It is quieter than my old 14" single in dual out muffler dumped out the side with the stock y-pipe and cats. My only complaint is that the sound is bleh, it's a boring sound, not throaty, but it is deep. So I put a 4" cutout at the bottom of the downpipe before the cat It kind of sounds like a V6 with is open, but the spooling turbo sound makes up for it

 

Ok Thats exactly what I needed to hear. Those clips are too loud for me. It's amazing how much of a difference there is between a 4" exhaust and a 3.5" exhaust. From what I understand the 3.5's are totally manageable.

Running 12# or so through a 6.0 I wonder how much power you give up with a 3.5 vs the 4.

 

Mine has a Twister muffler, a huge Flopro reverse-flow muffler, a Helmholz resonator and a resonator tip and it still drones and is pretty loud. Not sure what I'm gonna to do with it next. I'd probably go a different route if given another chance, but it's not too bad, I'm probably just getting too old. Some days I love it and some days I hate it.

Compared to a friend's dual 3" its as quiet as a church mouse.

 

Thats interesting... im sure he's not trying to keep it quiet though. I think you can make anything loud... but it becomes a problem when you CAN'T make it quiet.

That being said, I wonder if I should think about dual 3" with an x and some big 3" magnaflow mufflers...

 

going 4-inch single also gonna run a magnaflow diesel catback