Muffler City is hit and miss on their work and customer service is pretty poor. I'm not sure how they stay in business to be honest. I have no personal vendetta with them or anything, just saying how it is.
Jim's Muffler is a great shop, but I heard they closed. Would be worth giving them a call to find out though.
Any auto/muffler shop can bolt on a kit exhaust. I recommended 5 Star Auto since Kurt and Dan are great guys with a really fair price. They are on Lake Otis
Also there is Underground Performance, I can't remember what street that's on (opened up not that long ago). A fellow named Nick runs it. He's a great guy and is very into diesel performance.
If you all are wondering, I lived in Anchorage for 4 years, moved to Idaho at the end of 05.