Ok, had it on for a few days now and I'm learning how to drive with it both with ECT on and off (hopefully this helps for those who don't have ECT Power). For reference, this was done on a supercharged engine running at 10 PSI max, 50% higher than a stock supercharger with fuel mods.
Normal driving around town and in traffic, etc there's little change which is a good thing. Shifts are quiet and smooth, no noticeable difference for the average driver. The 2-3 shift is a bit quicker but it feels the same. ECT on makes it hold the RPM's a bit higher than usual, close to 3k RPM but nothing crazy since it did that before.
At about 1/2 or more throttle is when you notice the change. The shift is very quick and there's a little "jolt" snapping into the next gear. Acceleration is a bit of a jump but once again nothing crazy. The difference here is that with the ECT Power off (or for those that don't have it) the transmission shifts at higher RPM's and doesn't bog down at low RPM's. Those without a supercharger won't know quite what I'm talking about here but that's ok. Basically it acts as if you had ECT power on, without it on. And with it on, it revs about 3k RPM before shifting, allowing you to use more of the power band.
WOT runs - This is where it is noticed the most. I used the "truck" settings not the "hot rod" because I didn't want it to shift funny at normal driving speeds for my wife. She drives pretty conservative anyway. At wide-open-throttle, this kit shifts VERY fast. My 1-2 shift didn't change a ton, but it no longer jumps around searching for a gear like it did before with not ECT Power on. I basically always kept ECT on, since without it the gears would not downshift and it would bog down at sub-3k RPM's and not respond well. Now it act like it should. Once again, not sure if those without a supercharger will know what I mean by this but those that do will understand. This also helps eliminate the "low RPM ping" that many complain about since it won't stay at low RPM's with any substantial boost. With ECT Power on at WOT - I have yet to try this more. The few times I did it responded nicely and rev'd very high and used all of the power band, which it USUALLY did before but once again, the stock transmission acts funny sometimes and once in a while it would upshift then immediately downshift again, which basically robbed power and make for a very jerky ride. It has yet to do this and shifts fast (read: it jerks because it shifts so fast!). I don't have any times to share comparisons though and a video does not do the kit any justice since it is felt by the driver, not observed.
My conclusion - This kit does not magically "unlock tons of HP" or something like that. What it does is shorten shift times and gets rid of lazy shifts especially going from 2-3 but also 1-2, and helps hold a gear higher under more normal/aggressive driving. Of course, if you are on a track quicker shifts equals faster times but that's not what I was after.
Contrary to what you'll read online about Gadget's thoughts on a valve body upgrade being necessary (some of you will recognize his site here:
Transmission Modifications) the stock transmission works fine. As long as you have an external cooler on it or change the fluid regularly there's no issues. Performance wise it acts funny, especially once you go beyond just a stock supercharger since it'll search for gears sometimes but nothing that threatens the integrity of the transmission. Those with ECT Power will notice it cleans it up a bit, but not entirely. This kit makes it work in sync with the extra power nicely. However, being that we have only a 4 speed transmission and in WOT situations you're only using 3 gears, this only is affecting two shifts. That's why it's not a huge game-changer. If we had a 5-speed or 6-speed, this would be a whole different story!
This is not for the average DIY'er, which I consider myself to be. Without the help here on the forums I would not have been able to successfully complete the job and I almost took on more than I could handle. Do this upgrade at your own risk and have a contingency plan if your transmission doesn't work right after the install.