LOL sorry guys. To start its only for 02-05s, the design changed in 06.
It basically does what a transmission line booster does (Sonnax). When you put your foot in the go pedal it extends your 1-2 shift. On my truck the shift is a bit rough, but shouldnt hurt anything. In short (or the way I see it), it takes the cushy cush that the ladies like out of the transmission. Ive never raced but I could imagine when you are trying to show an S10 whos boss that extra second or so that is saved by your truck not making the "perfect" shift could save a lot of embarrassment.
It involves finding terminal 10 on the plug that goes into the TCM just behind the air box. A quick google search can get you guys more info then I can right now, I cant link to another forum which is where the info is all at. Sorry to be so vague.
Sure it'll suck, but it'll make you a man