Basically, if I am not mistaken, it gives firmer shifts in gears 1 and 2. It does seem to be an improvement, especially at highway speeds. check out some more info here, beer:
http://www.automotiveforums.com/vbul...d.php?t=405647
The part is cheap, and it didn't take very long to do, and I had NO idea what I was doing beforehand.