It's not actually a rebuild kit. It's similar to all the shift kits on the market for older cars. It's hardware to be put into the valvebody. Takes roughly 2 hrs to install. I asked if he had and before and after claims at the track and he said "not yet" He said if I bought it, he'd be very happy to have me get him the info, good or bad. They are working on a better kit right now and hope to release it in a month. TransGo had that I know of, always been pretty straight forward and had great success with thier products and pricing.
It firms up the shift a "fair" amount. He said he's sure it will help in the 1/4. Obviously it's better for the trans with less slipping.
I dunno, I may buy it.... not expensive but I'd really like to have some feedback from a recent buyer.