As Blue93 said, Turbopeople and Laroccas, but you could also try Kauffmans in PA. I think they have some experience in turbo tuning. Last year when I was deciding whether or not to get my car tuned I called both Turbopeople and Laroccas. After I spoke with the guys at Laroccas, my opinion of them was not a positive one. First off, they were very rude to me on the phone and second they seemed like they had no experience in turbos. The price was also very expensive for a burned chip and tune. Around 7-800 dollars IIRC. The guy asked what I had and I told him, stock longblock with T64 at 16lbs. I could remember his response quite vividly; he said that my car would probably make around 400 horsepower and that I would not be anywhere near splitting the stock block.LOL. After I heard that I said no thanks.
Speaking to Turbopeople was a far better experience but they would only tune my car if I had a engine mangement system which I didnt. Those guys were definitely cool though.