I just wanted to post that the FAQs on the door mirror replacement were helpful. However I just wanted to reiterate that the 8 tabs to be released(2 for each corner) are very susceptible to re-engaging as you try to work your way to each of them. It takes LOTS of patience but it does work. It took me about 30-40 minutes of gentle finaggling to eventually release all of them. Since the mirror I wanted to remove was cracked I didn't worry about mangling the tabs, so I twisted them back to the point of almost breaking them. That only worked on the top tabs. But I was still careful because I didn't want the glass to crack and fall to pieces.

It would help to have a hooked screwdriver or a pick with a bent tip, if there is such a thing, would require the maneuvering. I used a narrow flat 7" inch screwdriver. I was also thinking that inserting something like collar stays or flat toothpicks between the plastic ring and the locking tabs as each one is released to keep it from re-engaging might have made the job go faster.