Exotic Exhaust Sound Massive 4.5" Design SS304 Stainless Steel Saves 15lbs Over OEM The ARM S58 4.5" Single Midpipe upgrade is designed to unleash the incredible exhaust sounds from your G8X M3/M4. By removing the secondary catalysts and two middle resonators, the ARM S58 Single Midpipe substantially improves the sound of your S58-powered BMW. Also, by retaining the OEM muffler, you still have the ability to control the exhaust valves, allowing you to close them for a more subtle tone for when you want to be quiet, or open the valves for maximum sound.The ARM S58 Midpipe is a 4.5" design from the downpipe connection all the way to the rear section where it will reduce to 2.75" to perfectly connect to the OEM muffler section. The ARM S58 Single Midpipe starts with an OEM-style 2-Bolt flange which can mate up to either the OEM downpipes, or upgraded downpipes that fit the OEM exhaust. These flanges will accommodate the OEM midpipe gasket perfectly. The ARM S58 Single Midpipe then transitions to the 4.5" Midpipe section of the exhaust via the slip-fit connections. Where the exhaust merges is the heart of the ARM S58 Single Midpipe. You have the 4.5" Single Midpipe section, this is where the magic happens. The sound waves of each bank of your S58 engine are combined to produce a much deeper and richer exhaust note.
