One problem related to seats has been reported for the 2006 BMW 5 Series. The most recently reported issues are listed below.
The passenger seat airbag malfunctioned casing the seat to have to be removed and sensor replaced. There was a recall on this but my car, and 2 of my friends cars were not included on the recall, my friends were charged by the dealership. My engine leaks oil onto the exhaust manifold causing smoke in the cab and potential fire hazard. On every bm I have ever owned the radiator leaks fluid which is environmentally hazardous and should have been recalled.