Well my 01 330 rattles near the rear of the car. i took it to the local bmw people and they told me it was "the shelf" behind the rear seats. it rattles when my bass isnt even on. its more of a shaky rattle. i dont know any other way to explain it. the people at the bmw place said it would be 500-600 to repair it. Does anyone have any clue what im talking about? or suggestions/directions on fixing this rattle myself and saving some $ ?