MTate,
At 140,000 miles I would give you the advise to have one of the major transmission vendors go completely through your trans or get an exchange from them. If your truck only had 30,000 to 40,000 miles I think you could get away with only a T/C and valve body, depending on how much power you're going to add. Coming from a heavy equip. service dept. back ground I have learned that there is only so much life built into components, bearings, clutches, plates, etc... When my truck only had 13,000 miles on it, I put an Edge EZ on it and shortly after I started to feel a slight shudder when the T/C went into lock up on a hard acceleration. Also when I installed the EZ I didn't feel much difference until lock up because the the factory T/C efficiency is so lousy. The points I'm trying to make is at 140,000 miles, the trans. has a lot of wear in it and if your going to add power to your engine you're going to stress an already marginal trans "47RE", plus you won't feel a lot of the power until you get a better T/C in it. The only other recommendation is to try and find a reputable vendor/installer that is familiar with the trans of choice to do the rebuild/install. I went up to Abbotsford B. C. and had DTT themselves do my complete trans and it has been the best upgrade I've done to my truck. I wish you luck with your decision.
Regards, Mike.