Developed for the BMW E39 540, this Billy Boat Performance Exhaust axle back exhaust is precision crafted using 100% T304 stainless steel. Through a combination of sound cancelation and absorption the straight through design muffler offers a deep rich exhaust note on acceleration with a mild tone at idle and cruising speeds. This along with CNC mandrel bent tubing allows for a smooth uninterrupted exhaust flow for increased horsepower and torque. A simple cut is needed to remove the stock muffler and the B&B system mounts in the factory hangers for an easy do it yourself installation. With no cutout in the rear fascia B&B uses their stealth turn down tip. No engine management sensors are moved or altered therefore this system is 50 state emissions legal and is backed with their limited LIFETIME warranty.