front window replace
The front window on my new/used E60 was replaced at some point in the past. The glass is not from BMW. Between 65-75mph the are 2 places along the window that generate a very high frequency whistle in the cabin. It's not loud, but it gives me a slight headache after a while. I found one of the spots and eliminated the sound by stuffing some foam gasket material into the space between the headliner and the glass (invisible from inside or outside). I've not found the other source, but it's somewhere around the front glass. Also, I noticed that the exterior trim on the left/right side of the window are not as stiffly pressed down on the glass as on other E60's with original windshields.
Summary: have your window done by the dealer using OE parts to increase the likelihood the job is done to OE specs. I'll probably replace this window at the dealer as I'm worried that the tiny leaks that cause these whistles may let in some moisture as well.