While looks are important, the auditory advantages are what any enthusiast is truly after with an exhaust system, and the Dinan offering for the G01/G02 M40i platform delivers in spades. For not only aural enhancement via the elimination of the central collector/resonator, but also weight savings and simplicity. The stock single-to-dual pipe setup has been abandoned in favor of an enlarged, straight, unrestricted, and freer flowing single pipe system. This pathway feeds into a Helmholtz equipped muffler that limits frequencies associated with drone, as well as assists in altering the overall tone of the setup to deliver the signature low Dinan rumble. The no-nonsense design allows versatility in volume levels with the retained factory valve functionality. Go from refined when cruising (low RPM’s) to rowdy when in it (high RPM’s), with ease. Or better yet, pair the system with an exhaust valve remote and have full control of elevating or reducing the sound! When open, the system behaves as a straight pipe solution that promotes maximum flow and volume for an exhilarating and forceful chorus. When the valve is closed however, exhaust gases are wholly redirected through the muffler and emit more tempered vocals acceptable for even the most sensitive ears. It is the perfect blend of civility when cruising or the full spectrum of auditory delight when in the throttle. No matter the situation, the Dinan valved cat-back exhaust system is the answer for the discerning enthusiast looking for sound without sacrifice.