I go to Henderson muffler, never had them look under the hood. They put it on the dyno and put a tester in the exhaust pipe, run it and give me my completed smog (actually they send it to DMV for you) I get a discount coupon for $40,00 each year and their closest to me so I have always taken it there. Although mine is totally stock and have no issues I would recommend them if your willing to drive tyo Hendo.
Terry