Dry window weather strip

Aside from replacing what aprears to be a dry weather strip, does anyone hv a recomendation that will eliminate the "squeal" when lowering the driver's window on my 98 5series ?? I am thinking silicon or armerol. A product that will eliminate a continual oily residue on the glass would be ideal.

Thanks

I use spray silicone. It does not seem to leave a residue and it "rehydrates" the rubber.

Wurth makes a great product that I've used quite a bit on all the rubber seals on our cars:

http://www.autogeek.net/wurth-rubber-care.html

Some BMW dealers carry it in their parts store.