I didn't read this entire thread, but I stumbled upon this thread on PH a few weeks ago while researching this. My new 340 seems to have excessive wind noise from the driver side mirror area.
They isolated it to a small gap between the A-pillar and windshield. It was fixed by applying tape (still trying to find a more permanent solution).
https://www.pistonheads.com/gassing/...f=72&t=1583831 (last page of thread)