I dont know about Dr Gas, but I have Moroso SpinTech mufflers on my C15 truck... They are FREAKING LOUD. I work in town so I'm waiting for one of the anal city cops to give me a ticket.. so far I've been okay.
IMO they are too loud. When I start up it cracks to life, idle is a good rumble, and when I open her up they scream. They're cool for letting people know I'm around if I wanna get their attention, but it can also suck when I'm trying to be quiet. I dont wanna piss off all my neighbors too badly.
They look just like short glasspacks. Very small, they are.
a couple of freinds have them,one with a Dr Gas x pipe and spin techs and the other with just the mufflers.They sound pretty sweet and they arent that loud(to me).
I am running the dr. gas x-pipe and spintech prostreets they are louder than other mufflers but I like it that way. They have an amazing sound and really scream the more you wind into it; however, I haven't heard how loud it is yet with the mods in my sig but I will soon so I will let you guys know then.