My xD is still doing it, though strangely the pitch of the whistling has changed to being almost out of my range of hearing, so it's somewhat more tolerable now, plus with winter coming up I won't be rolling my window down for the next few months anyways
. I still haven't figured out where exactly on the mirror is causing the issue; visually there seems to be no difference from the passenger mirror, and I can't exactly climb out there while on the freeway to mess with it
Between the whistling, the rattling in the dash, and the bluetooth module being dead in the AVIC it may be time for a visit to the dealership.