Dinan Free Flow Axle-Back ExhaustUtilizing the same muffler as its B58 siblings the G30 540i exhaust improves exhaust flow by reducing back pressure, resulting in increased power output and a great sporty sound that is civilized when you want it to be, and pleasantly aggressive under hard acceleration. Not only is the tone improved but the additional burbles and pops that also accompany it are simply intoxicating. While on the exterior the sound may be viewed as aggressive the inside