Kartattack-
Sorry for the late reply, didn't see this.
About my 4" Summit System. It held up great for the time I had it on the truck. Yeah, I goofed, it was just too darn loud for me.. at around 2,000rpms and up it was just too loud for me, not to mention acceleration, and I feared what it would sound like under load pulling our 10,000lb 5er. It was definitly much louder than stock, but kept trying to tell myself it wasn't that bad and I would get used to it. My ears would clog up on half hour trips as well. I had thoughts about dynomating the inside of the truck, but would cost more than a couple of mufflers. I decided that I would put the stock system back on, as I didn't cut it, and do some research on mufflers and maybe be able to put it back on in the Spring if I could find a quiet one. If not oh well, lesson learned, at least I was only out $300. Probably not what you wanted to hear, but I guess some like the noise, some don't. It sure did sound good on WOT runs, but wasn't practical for the long highway commute to work...
Bob