Kev's Muffler & Brake in Gladstone. (NW 72nd St, near the bowling alley and kinda tucked in behind things.) It's kind of a dirty shop and I wouldn't wait with it if I didn't have to - find a ride and come back for it.
They've always done really well by me, and when I had an issue they couldn't fix (their computer wasn't current enough for the codes/errors I had) they referred me over to Brad's on N. Oak at 74th. Also did right by me.
Recommend for Kev's: first time I was there, dude dropped off his AC Cobra for service.
I needed an exhaust on my truck. He got it on the rack, looked it over, grabbed me and said "here's the issue - bunch of little holes where it rusted out. I can order the factory part, it'll be $300-350 and here in three days, or I can fab up the Y pipe now ... probably 75 bucks and take me an hour."