Friend of mine lives in Sun City, I met him at his house to go out and meet some friends further southwest of where he lives. We got back to his house around 11-12 PM. It is quiet in those communities and even with the Donaldson resonator, the Walker 42" muffler the hiss was louder than you might think with window rolled down and I was just going about 15-20 mph. Next is Donaldson 11" diameter offset muffler, flows at about 1820cfm which is plenty for the Dmax engine. I prefer to be a kid, seen not heard.....