I was able to help mine, a little, by lubricating the drive cable (or whatever you want to call it). I also rerouted the cable housing that is on the "exhaust" side of the motor. It's the black tube you can see coming up from the motor below. I was able to relax the bend a bit so it moved easier inside.
If you do take your door apart to do anything, it'd probably be worth checking the voltage at the motor too when it's running. I didn't do that, but there's a chance some upgrading wiring could help if the voltage is low.