My cat-less/resonator-less 3" isn't too loud. I don't car about volume. There's good loud, and bad loud. With no catalytic converter, or resonator the car sounds like a dump truck, and is annoyingly buzzy at certain rpms/gears; in general very "raspy". That's my goal is to quelch the rasp, and hopefully the volume down overall slightly.
There was a video I ran into here and saved. Can't find the original post. The vid was named "Mike's Custom 3 inch" I believe. Shows a black SRT startup, a few revs, and some footage of it running up/down a two lane highway. Anyway, if anyone remembers the vid; THAT is what an SRT should sound like.