UPDATE: PROBLEM SOLVED >>>>
So I had basically lost audio in my driver door permanently. Every once and awhile it would come on and during a long drive the bumps would cut out the sound. Then I noticed the passenger side started doing this as well, but not as badly. I took my car to a guy up here in NNJ to take a look at it. He's been w BMW and MB for 16 years and knows the navi and radio units quite well. We Swapped out actual navigation head unit entirely, but with no luck still did not have audio in the door. We then tried the radio/cd tuner located in the trunk (drivers' side) and that finally worked. Its been a few days without the slightest hint of a problem. This appears to be the source of the problem so if anyone has the issue of losing sound only in particular areas/speakers check your tuner!