If you're talking about the accumulator spring, leave it out. That's not causing your issue, nor is excessive shift pressure. That will not bend a driveshaft. Twist the hell out of it, yes. Bend it into runout? Not gonna happen unless you've got some seriously neglected U-joints. From your posts about this car I'm guessing that isn't the issue. Something else caused this, such as being leaned in a corner for too long or something being set on it while it was out of the car. That's assuming the runout is in the center of the shaft. If it's at one of the ends, you might want to have a peek at your output shaft bushing or your front pinion bearing, but again--I would assume you'd notice if there was wobble in either yoke.
It can be straightened, but how long are you going to trust it? Fatigue is fatigue... the old "how many times can you bend a paper clip" scenario. Racers will paint a white stripe down the length of the driveshaft as a gauge to show them how far it's been twisted, and when it's time to replace it. You'd be surprised how far they can twist without failing.
