I really want heated mirrors. I am tired of the scrape.
As I find time I will update the procedure.
Mirror removal. Easiest trick with a factory mirror is to grasp the bottom outside of the mirror. Get your fingers behind the mirror and pull it toward the car. A factory mirror will pop.
Separate mirror from holder. Use hot tap water and heat up the outer plastic holder and gently bend the plastic rim off of the glass mirror. Start at one corner and work it around the edge. Keep the plastic hot and pliable with hot water. Patience.
Separate adhesive from the mirror. DO NOT USE ANYTHING OTHER THAN A SOLVENT. Your finger nail will scratch the coating! Use a solvent to dissolve the 3M adhesive. It will take some time. I used camping/coleman stove fuel. I poured a small amount on the mirror and used my finger to rub the solvent onto the adhesive. The backing is super easy to scratch so take your time.
Next is drilling out the holder and mounting the mirror.