Help picking transmission parts.

I know there are a few dealership guys here good with transmissions. My transmission is slipping really bad and it is coming time to rebuild it. I planned on buying the $900 Monster in a Box kit but now I am thinking it may be overkill and it would be nice to spend the rest on headers. What all is required for a stock rebuild with a few performance parts tossed in? I will ditch my shift kit for the Transgo and will probaby go with this kit (unless there is something better) . What else will I need to build it to hold up to my 4.8?

Go with overkill.