What do I need for my 904 rebuild?

A stock rebuild kit is all I can see you requiring, If any upgrades.. I like the .999 Planetary gears, they get you out of the "Hole" quickly. Also the Trans-Go shift kit is nice, it will prolong the life of the transmission due to minimalizing slippage during the *****. I also would replace the torque convertor with a new unit. Hope this helps.