If want want to save a little money, and get a great tune for a GM I would recommend my shop. Brian does good work, but if you'll notice he is the resident ford tuner in central ohio, an also now does GM, and I am not implying he has no clue about tuning your GM product.
We have tuned hundreds of GM product now, from crazy compact circle track cars to 950hp twin turbo vettes. If you want to pm me or call I can give you all the details you need.