One problem related to manifold/header/muffler/tail pipe has been reported for the 2008 BMW 328. The most recently reported issues are listed below.
Valve cover gasket leaks oil on exhaust manifold creating burning smell inside the passenger cabin. This creates a fire hazard with oil on hot exhaust manifold. When starting car in the morning is when the smell is the strongest and last throughout the drive. This is a dangerous problem and should be recalled. Parking vehicle in garage can burn house down if oil causes fire!.