I've had all of the problems mentioned above, and have fixed all of them.
Want to know how?
318ti.org!
Read this write up, and perform every single step one by one.
http://www.318ti.org/forum/showthread.php?t=20666 I know it was mentioned already earlier in the thread, and I make no guarantees, but it is the de-facto best read available online for repairing 318ti (and even e36) window problems.
I had to buy a guide rail, buy the felt, replace plastic sliders, unbend a regulator, and restore the door panel. It took time and patience, but following every step of the guide worked beautifully. Its well explained.
It easily assisted me in understanding all of the mechanics of the Window Regulatory functions, and allowed me to simply repair the problems.
If you need pictures, I will be taking my door panels off again shortly and can even probably provide some.
Hope it helps!