i have lived here all my life and asked this question so many times, but there arent very many speed shops around here. There is a shop near dulles airport called mach 5. They had a blown magnum with 600 to the crank, a nice *** viper with over 500 to the wheel and i think it was a 57 chevelle with an ls1 swap goin in it. They can build engines, exhaust, suspension, whatever, cept they dont have gm software so u'd have to find another tuner. They also do custom exhaust, TiG welding, mandrel bends, etc. I will say one thing tho, they are mainly an import shop. Ill be takin my car there to get suspension stuff installed and allign my suspension, maybe some engine work but thats about it.