Originally Posted by rkjunior
make sure its a newer STI for donor mirrors. I bought a set from an 08 and the harness was different.
The difference is heated or not heated mirrors. 08-10 STI has unheated, 11+ has heated mirrors. Heated have a 10-pin connector, non-heated have an 8-pin connector.
They are easy to re-pin to another connector housing, but if you are buying whole mirrors you'll want to get them to match whether you have heat or not.