Tranny experts - 722.358 rebuild

[brabus3.6]

Okay so my W124 1989 Brabus 3.6 was slipping on the 2-3 shift a few months back so I swapped it out for a second hand unit knowing that it probably wouldn't last too long with the extra torque my motor is putting out. I want to rebuild the 722.358 tranny that came out of the car and reinstall it with the hope of getting another 100,000 mile stint out of it. Checking transmission codes I see that my tranny is a standard 300E unit so it may well be that Brabus did nothing to prepare it for the extra torque it now deals with. Which parts should be replaced in such a rebuild esp. in lieu of the problem? Are there any heavier duty items I can can use in the rebuild from 400/500E trannies? Part numbers would be appreciated. Thank you