I have cut and shortened many driveshafts myself in my driveway. I do not cut the front; only the rear. I do not use tubing cutters because they leave a ridge. I take a piece of cardboard and wrap it around the driveshaft next to the weld and mark it all the way around; slightly into the weld; like <1/8". You want a straight cut so the tube goes back on the yoke a maximum amount. I use a Harbor Freight angle grinder and cut slightly into the weld. First mark the yoke and up the driveshaft past where you're going to shorten it; so you can line up the marks to weld it. Mark the location of any weights and weld them back on in the same place. Tap the yoke into the shortened driveshaft and install it into the car. Use a dial indicator to center the driveshaft. Do not turn the driveshaft; use the wheels; carefully and slowly. Tack weld in THREE places. You can change the angle by cutting ONE weld if you use three points, but you can't with four. After dial indicating and cutting and retacking, remove the driveshaft and weld it about a half inch at a time; starting at the tacks.
