Dinan Valved Cat Back ExhaustLooking to elevate the acoustics of your X3 M40i X4 M40i with an exhaust system that not only offers a much improved sound while retaining the the flexibility associated with valves, but also raises the eye appeal beyond the mundane? Look no further than the Dinan valved cat back to meet all your needs and then some! The full cat back requires no cutting and utilizes factory mounting locations that allow the Dinan exhaust system to be a