I ordered and installed one years ago when I first got the 325ic from my father. Like the PP, I had to take it out and put it back in a couple times...like timing belts, one tooth off and it just doesn't work. It buckled and warped. But once I got it in just right, it looked great.
My only problem was the new window is apparently is apparently not made to exactly the same dimensions as the old, and the canvas flap that's supposed to tuck in under the seal of the window doesn't reach that seal in some places, notably the corners. It's irritating, but I've learned to live with it.
<img src='http://www.tinsmithtech.com/graphics/sigpic.JPG' border='0' alt='user posted image' />
Dad's 1992 325iC