i looked at getting one from chiptorque a while back for my v6...price was almost $500 and after three emails they still wouldnt disclose just how much improvement i would get in raw figures.
i ended up gettin a chip from dr bob (on this forum) for a fraction of what chiptorque were asking and it was an awesome improvement with the bolt-ons i already had.
i realise i havent helped with your question all that much, but i guess what im saying is that chiptorque are a little hard to deal with and overpriced in my view.