I have a 2003 H. O. Cummins in a 2500 quad cab. The thing I like about it is how quiet both the exhaust and engine are, compared to the old 24V anyway. I was wondering if anyone knows of an exhaust manufacturer that builds a decent 4" exhaust that flows well, but remains quiet. I've added an Edge Juice w/ attitude module and plan on many other mods in the near future. I just don't like the overbearing noise of some sytems, you know, the ones with a muffler that is about 2" bigger in diameter than the tubing itself. I don't know if the stock exhuast has too much back pressure for a moderately modified engine. It might not be able dissipate enough heat forcing E. G. T. s too high. Maybe I'm just asking for too much. Anybody's input would be greatly appreciated. Thanks