Welcome to the full exhaust suite for the BMW F85/F86 platform. Connecting to stock or aftermarket free flow downpipes the valved exhaust measures 2.75 inches from inlet to outlet. This system runs unrestricted all the way back to the tips. In our testing and development of this platform, we found that running the setup unresonated provided a more raw sound experience and insane snaps when you change gears. This system reuses the OEM factory electronic valves. The system is available in T-304 Stainless steel. The S63 sounds decent from the factory but at Valvetronic Designs, decent doesn't cut it.