Re the defroster
That happened to me and they replaced he rear window. That fixed that issue.

However, since day one I've had intermittent faint static even with the radio off!
Since it's intermittent they could never find - fix that problem.

Happens in all kinds of weather and seasons.

I have a 2006 X5 3.0 - standard radio. Only addition is a hard wired Valentine One in the headliner with a remote in the ash tray.

__________________
"Know what you know and know what you don't know"

GEN. G. S. Patton, Jr