I had the TransGo shift kit in my LS for a little while before I swapped to a manual. You can get it through summitracing for under $100. If you have never done any type of transmission work, I highly suggest you getting a shop to install this kit. I also highly recommend you getting a transmission cooler too.
I think I have a wright up somewhere on here, but like PD ^^^^^ said, the SC forum has more info on it.
AKA "Dirty Mike"
(93 LS4) - 5spd swap, Megan coils, 95+ big brakes with Goodridge stainless brake lines. S&S Headers with a custom exhaust, Motegi Touge's 18x9F and 18x10R, Welded diff, and vortech/procharger coming soon..... Best 1/4 mile so far 14.9 @ 97