I've had a COBB SS 3" (quote/unquote) exhaust for several years. It was loud, obnoxious, and as I came to find out, not truly 3" all the way through (restrictive donut gasket, and closer to 2" after the y-pipe!). The ETS quiet exhaust with resonator has been an incredible upgrade. It's quiet enough to be friendly for passengers/daily driving, but still has a wonderful aggressive rasp at WOT. No more drone on the highway! It's also a true 3" all the way back, and the difference in power was obvious. Really impressive product all around, would recommend.