Need new tranny for my 6.0!!!

[powerstroke59]

I think my tranny is shot. Slipping really bad. Somedays won't go into gear at all. Thinking about upgrading bc I do have tuner,intake, exhaust, and head studs. I've been looking at ATS stage 2 but not sure what I should go with. Any suggestions?? Any help would be appreciated. Thanks

[Tuscany]

Really depends on what your overall goals are with the truck. If your not planning bigger injectors, bigger turbo and anything over 550 rwhp just go with a rebuilt stock 5r110.