Cover, air duct, painted left — a genuine BMW part, number 51 11 0 002 118. The number stamped on the part is 51110002118; BMW's catalog files it under the short number 0002118. You will find it on our Interior Body shelf, under Other Body equipment parts.
It fits the E46 sedan (318d, 320d and 330d, 1998–2004), with the M47, M47N, M57 or M57N engines.
BMW draws it on the M trim panel, front (51_3694) diagram. It weighs about 37 g (under 0.1 lb).
We have not had one on the shelf yet. Request it and we will tell you when one comes off a car.