There's Competition Specialties in MA. They do
amazing work. Do a search for the name Comp-Spec on here and you'll see their work first hand. (Or just look up KARMA. They did most of the work on that car.)
Also, there is Prodigy Customs down in Florida. I believe DSE is on the east coast as well. ALL of these companies are very reputable. They all do great work.
Good luck.