The center section of the 335i is a restrictive piece including a center resonator, designed to keep the sound muffled. If your looking to add an aggressive sound, while keeping the stock mufflers this is your answer.

A direct bolt in piece, all you need to do is unbolt the sleeve clamps and install the Billy Boat system.

Not for sale or use in the state of California on any pollution-controlled vehicle as per the California Air Resources Board.