I agree with Alan, as an alternate I've used Performance Coatings, Inc.in Jonesboro, GA without an issue at all. Their number is (770) 478-2775. I needed a really fast turnaround but perhaps Kevin can do the same for you if that's needed.
There aren't any merits for interior coating but don't recall all the techical specifics. A good thread that SSDiv6 (his line of work makes him a very credible resource on many things) and others chipped in on as well discusses this along with stainless matl use, I've included a link to that here. I also wouldn't hesitate to call Mark Lelchook at Performance Welding, he's VERY helpful and knowledgeable on all exhaust topics.
http://classracer.com/classforum/sho...llector&page=2