@Power6 — Do I just wire the signals into the existing mirror connector on my '11 Limited WRX? Does that connector on my heated WRX mirror have the leads to make it all work?
Buying the caps and signals new from subarugenuineparts.com or from you to make this happen ain't a problem.
If I'm not mistaken these are the part numbers I'd need:
Lamps: 84401AG042, 84401AG052
Covers: 91054AG061, 91054AG071
Edit: I answered my own question. Pulled the door panel off and checked the connectors. The connector on the end of the mirror wires have no leads in terminals 1 and 5, so it's definitely not as simple as inserting new wires from the LEDs and reconnecting.