If you havent started your build yet, set some time to watch my 700R4 and 4L60E "high perf" videos in each respective playlist. I create and publish them to quickly share large quantites of information specific to those transmissions, that would otherwise take much longer to explain. There's plenty of content that will give you ideas of what to do and how to do it. Obviously, feel free to ask questions along the way.
The main areas of weakness of those transmissions are the TV boost, plunger/sleeve, pump, 3-4 clutch (under engineered in general and esp relative to engines these units frequently see today), band (usually too much clearance, too aggressive a hydraulic calibration, reuse of reverse drums with warped surfaces) and sun shell.
Focus your attn and resources beefing up those areas and you'll be good
The gear train/output shaft is fine, as is the input shaft and drum as long as they dont leak. Gear lube mods help with longevity and a Sonnax Smart Shell is a great bang for your buck upgrade. Pair it with the 03+ reaction shaft and you're set with that part of the trans.
The rest of the clutch packs arent overly vulnerable and easy to set up correctly - add 97+ bonded steel/rubber apply pistons and the fwd return spring to go with them and you're set. Later valve bodies aren't fussy and hydraulic mods are straight-forward...Also, remove the tcc check ball in the snout of the input shaft and install the 4L60E equivalent to get more TCC apply fluid to the converter clutch quicker...
