they knock it in comparison to banks or borla. Ive talked to ppl who had dynomax (years ago) and the muffler rotted out within a year. They weren't running the stainless version however, i expect that to last a bit longer. Stock pipe size is 2 inch, banks runs 2.5inch and dynomax only runs 2.25, its still better than stock-some would argue its much better than stock and pretty much all you need out of the 4 banger. When it comes to quality and performance, from what ive heard, nothing compares to banks headers and catback setup. This will of course run you quite a bit of $$ so if ur strapped for $$ like i am, you may wanna consider the set up i went with-which is the ultra flow muffler and tailpipe-not the super turbo kit they sell at quadratec.