Spacers not sure, some people use them.
Windows need to be down for quick access by the emergency response teams if needed. Also, helps awareness. Like the corner workers yelling at you for missing flags, etc.
2008 E92 M3 Jerez Black,DCT,Fox Red ext,Prem,Tech,19", ipod/usb, CF roof and trim
2010 E91 328i Space Gray,Black int, M sport, most options
2007 Montego Blue 335i (retired)