Hypertech Power Programmer III.
 

I have been running with the power pragmmer tune for a few days and I can say I'm impressed with the unit. The programmer can change several different variables like tire size, rear end gear ratio, T-Stat temp and many more. The power tune did not make a huge difference but the car feels a bit more peppy and on a weird note my exhaust is louder and has a different tone then before it was programed. The shift firmness does make the car shift harder under heavy throttle and under light throttle conditions the transmission can shift so quick you can hardly even feel the car shifting at high speeds.

The main con to the HPP3 is the price of the unit, I was able to get mine for $150 shipped almost new (even came with the Hypertech stickers). See to the trick to owning one of these is to buy one at a low price and then just sell it for the same price you paid for. These things do not lose value over time so if your smart you can break even or maybe make a profit when you sell the programmer. Note this programmer works great if you have small bolt ons or a stock car but the power tune is VERY dangerous to use if you are running forced induction, nitrous (of any shot), or a large aftermarket cam.