Transmission, overhaul or replace?

[Astroman]

1981 300SD 270k miles. So It's just about time I'm afraid to overhaul my transmission. The question is, should I attempt this myself, take the car to a transmission shop, remove the transmission first and take it to a shop, or what? The overhaul kit from Fastlane says it comes with everything but the steel spacers, (are those re-useable?) for 260 bucks, but what about the brake bands? I can't imagine getting out of a transmission shop for under 1k, and a new (rebuilt I assume) trans looks to be about 1500. I've already done the B2 replacement, and the K1 accumulator spring etc. but I'm afraid it might be a lost cause.. So is it rocket surgery to do this myself on a bench, (I have skills, but not alot of time) or should I leave it to the experts and sneak another grand from the wife's vacation fund?