This is a 4-piece retrofit OEM LCI upgrade (for pre-LCI cars) mirror housing and front cap (parts 2 & 3 on the diagram), which we had painted in OEM BMW Cerium Grey or Gloss Black. The front cap (around the mirror) is always Gloss Black. It gives the M340i a much more modern look and it ties in with the Cerium Grey or Gloss black accents around the car.
We strongly recommend having this conversion done by your dealer, as it is quite challenging.