However, I would have just integrated the mirror defrost with the rear window defrost switch as done on later models. Nevertheless nice work.
How are you going to correct the viewing angles on the mirrors themselves? I've had to redesign the internals of my USDM mounts to allow them to accommodate my merged USDM/JDM bottom plate. This is due to the extra height created by merging the plates which is what got me the correct viewing angles.