I have Flowtech Stinger mufflers on my GT and they are quiter with an offroad-H pipe than brand new mustangs bone stock. They sound really deep and throaty when you get on the pedal, but at the same time it's not "loud". They're basically just a regular "turbo" muffler design with 3 perforated cores, and they're fairly heavy for a muffler, but i can see why because there's quite a bit of sound dampening. The only time people notice the sound of my car is when i'm accelerating or they're standing behind it. I imagine that with catalytic converters, those mufflers would be EXTREMELY quiet. The best part of them is although you hear the 2000rpm drone, you don't FEEL it and it's not loud enough to disrupt a conversation or overcome the radio. I'd recommend this muffler for exactly what you're asking for, it's about as loud as Dynomax Super turbos on a stock 5.0L with stock 4-cat H-pipe.
For someone looking for a ripping, screaming sound these mufflers are definately NOT what they'd be looking for.

Think I'll give those dynamax a try.


Skyler

There is a site called mustangexhaust.com that has many sound clips. You might want to try browsing through some of them. The Dynomax clips are fairly quiet in comparison to some of the others.

Sorry, but you really cant tell anything about loudness when you listen to those clips. They should give a decible figure for a given rpm for each, I have the Dynomax super turbos with two gutted cats and two removed. My car is very loud and I wanna fix that, but I still kinda like it, really impresses the clowns with fart cans on 4 cyl. cars. They dont wanna race, and I wouldnt anyway. Quiet exhaust is the mature way to go though. "Walk softly and carry a big stick".

I have Dynamax Super Turbo's on my stock 5.0 and they sounds very quite. Now im sure when im lining up for a race and i get on it they can hear me but all mustangs are pretty much that way. As for just cruising around town and hiway driving. they are slightly heard below 3K rpms and if you want quite i would suggest these.
Bryan