Theres this guy on grandamgt.com that's working on getting some rebuilt trannies for a decent price, looks like he's done a lot of research and he'll put in a LSD for you too, check it out.
http://www.grandamgt.com/forum/showthread.php?t=66593
I'm thinking after I get the turbo in my car I'll get my tranny rebuilt with an lsd to handle the abuse.