I tried the GForce chip. It was only $65, so I thought I'd give it a try. It connects to the IAT and, I assume, fools the ECU into increasing the boost.
GForce says to give it 100 miles "for your car's ECU to fully learn the new settings of your GForce Chip." At first I noticed no difference at all. But after some mileage I feel the car is stronger and more responsive both around town and at WOT. I would love to do some really objective testing, but don't have the time.
I do pay a lot of attention to my fuel mileage and have seen a definite improvement, mostly in highway driving. No so much around town.
I had been looking at the Trifecta tune which looks super, but at this point I'm quite satisfied with my car's performance for very few bucks.