Space Coast is an advertiser. His plating is top notch. What I found out the hard way is getting a set replated (about $800) is only a part of the cost. I believe the inability to disassemble the mirrors without damage is going to add significantly to the cost of replating. That assumes you value your time at zero.
And then there is the shaking. My current mirrors shook so bad it was impossible to see clearly, especially on the driver’s side. My solution was to jam foam rubber between the housing and the glass making them unadjustable.
I would be more optimistic about the practicality of disassembly and replating if the corrosion associated with dissimilar metals did not make it such a challenge taking things apart. I had to beat the head off the post it is attached to, and that goes into the arm. I had to beat the bolt that attaches the arm to the mounting plate in and out of the arm and mounting plate until it loosened enough to separate the two. I couldn’t loosen the two screws holding the convex mirrior head to the main head so I drilled the head off the screws. Drilling the remaining portion of the screws from the convex mirror head is not going to be easy because the harder screw material is going to try to push the drill into the softer aluminum. In short refinishing the mirrors is doable but not without some grief.
As to powder coating them, that is definitely an option, but requires the same effort to disassemble the entire mirror assembly. Powder coating requires elevated temperatures for a proper cure so heat sensitive components such as the motors and wires still have to be removed. Powder coating is like plating in the respect that the key to success is pre-treatment. Like copper coating as a prerequisite for chrome plating, a sophisticated aluminum pretreatment is required to insure adhesion to aluminum and resistance to the formation of corrosion beneath the poweder coated surface.
A remaining option is to not replate the parts, but to have the existing plating removed by a plater, and then polishing the raw aluminum (like so many of us have done to our wheels for years). Every option includes disassembly which is going to require effort and new parts to replace damaged ones.