Thanks!
dykzeulb, et al: That sounds like the issue. The window motor will make noise (clicking and whining), but the window won't move at all or it might intermittently move.
I've now done all four windows on my X, and it is really nice to be able to use my windows one handed again.
I did the first three, while the fourth was still working. Not a week later it started acting up - it would work but not reliably. When I pulled the motor, the bushings weren't <Marvin the Martian voice>completely disintegrated</Marvin> like the others. They were distorted and cracked, so I replaced them.
For others, one of my windows would inch down on its own over time (the passenger rear), and it had the same bushing issue. The front windows just wouldn't work, but would stay up. I suppose a result of the different lift mechanisms. (I found the front windows slightly easier, because I didn't have to blindly mate the motor regulator back to the pulley thing.
Oh, another tip I learned on the first one (driver's window). It really is a torx head screw, even if you can't see the outline because it's filled over with crud that matches the screw. And if you bend it out of the way, because you think you can't unscrew it, it will still work, you just have to work a little bit more to get it in place.
I did have to work at getting the bushings in, but my trick was to use a little grease to hold them in place, but have them sticking past the end of the metal gear part, so they were slightly pointing in. It was a rather tight fit, but it worked.