theres a very reputable trans guy in my area, he said drop it off and pick it up for 800, thats full rebuild with converter shift kit and a few little things he told me about to make the thing last longer, i have maybe 325 fwhp right now so im not too worried about it lasting for now, but im wondering if id be better off to get one from pro built or even just one of his rebuild kits, because i know later down the road ill be wanting more

See if you can find out what shift kit he will put in it, or let you specify. The B&M kits are junk, everyone seems to agree that a TransGo kit is the way to go. Also, I'd ask him about installing a corvette servo, and a 10 vane pump if your trans is an early model with the 7 vane (not required, but I've been told it flows more). I don't have any experience with probuilt transmissions, but if the price is about the same I'd probably go with them. Otherwise, I'd probably go wit the local guy.

i'd definately go with probuilt, great trans and great customer service, $800 seems like a pretty much stock rebuild, probably wont handle much more power than a stock transmission.