The kit is only a fraction of what needs addressed in an overhaul. Be careful with knock off parts and stuff from China. You are taliking like you want it to last so updates and known parts that fail that need replaced. Setting the proper clearance on build is critical VB wear is a huge issue on these units along with pump. I personally would look for a kit that used Borg Warner high energy frictions for the 3-4 pack. Just my opinion on overhauls. I get contacted after a DIY job won’t work after rebuild followed by a list of new parts installed. You can put hundreds of dollars of new parts in and destroy them in seconds. It’s not what you know in transmission repair it’s what you understand. This is a very doable transmission for the DIY just do your reasearch and don’t get caught up in the HP, super heavy duty parts lists that say you have to have them. Good luck and if you have any questions please feel free to ask. You may really enjoy transmission work, Lord knows we need some new blood in this industry.