Try Gel-gloss from Home Depot.
It works great and will leave your windows as smooth as silk. The water will sheet off, no need to use your wipers.
2004 E60 530is, Delivered 12/12/03, TiSilver/LGrey, PP, SP,PS, PDC, ACC, FRS, Step, Xenons, clear bra, body colored rear inserts. (Retired, 1983 henna red 320is)
2004 Corvette Z06 Commemorative Edition