Originally Posted by 328idogg
I think the answer is a poor choice of materials or manufacturing tolerances (my front passenger door doesn't squeak, for instance).
The fact is that the doors do wiggle around a small amount even when shut. The basic problem then is that you have rubber on plastic rubbing, and stiction means that it won't glide smoothly against each other - hence the noise. Note that the part of the door seal (red arrows above) that contacts the shadowline trim is relatively hard, whereas the main door seal that contacts the metal body is soft, so the latter doesn't have to slide against anything. RejeX/wax on the shadowline trim reduces the stiction. It's been working well for 1.5 months now. If you just lube the seals without waxing the shadlowline, it probably won't last very long.
You could also ask the dealer to apply teflon tape to that contact area on the trim, but I'm not a fan of that approach and would only do it as a last resort.
Makes sense. Just surprised this is an issue on a BMW. Seems like a pretty low-rent problem on a car made by such a quality oriented company. Also, I just had it detailed, but maybe he didn't hit the trim with wax since it's gotten worse since then. The most annoying thing is that I drove a Toyota 4Runner for three years before I got my 335 a few weeks ago and that thing was as quiet as a church mouse.