elderon

Hey all. I noticed my tranny is starting to slip just ever so slightly before i put her away for the season last fall. Given that Im making well over 400 HP at the motor now, I know its killing the 4l60E. Anyways I'm looking for some advice as far as what I should do about it. Im on a very limited budget. Basically I just want to have the tranny built up (and fixed if something is worn out) to handle the power the car is making. What should I have done and where should I take it? I know there are several local tranny shops in the tri cities area (Bay City Saginaw Midland) but none are particularly reputible for what kind of work I need done. Suggestions?