I think I paid about a $100 including shipping for the used OE pair (glass only) and thought I was getting a bargain compared to the OE price. Heater is not available separately. I could only tell that the resistance was off on one heater and it would barely warm up. I found a damaged trace when I took the plastic back off. I did try to fix it but the element won't take solder and my fix did not look like it would hold so I peeled an element off of another mirror.

__________________
1988 325is (purchased new) sold
2004 X5 3.0 2005 X3 2.5
2008 X5 3.0 (new to me)