Electrochromatic Side mirror replacement

[Unit107]

My wife did me the favor of taking out my driver's side mirror a few months ago while backing out of the garage. There wasn't alot of damage to the mirror assembly, other than the supporting ring, however she did manage to crack the mirror, which caused the glass to separate from the chromatic coating beneath.

The dealer quoted over $300 to replace just the glass, which I see is just about right. I was wondering if anyone had the pleasure of having to replace this item, and have done so on their own, and could answer a few questions:

1. Is there a inexpensive (relative to the dealer) place to get this mirror on-line, either OEM or high-quality non-OEM replacement?
2. Is this item pretty easy to change out without any special consideration or tools?
3. Before I disassemble, is there a code readily available on the back of the mirror to ensure I am ordering the correct part?

Thanks in advance.