This is a high-grade lightweight titanium system, finished with hand-crafted carbon-fibre tailpipes and a high-grade austenitic stainless-steel link pipe set. The valves in each side are calculated to tailor the sound, and two acoustic reflectors are fitted on the tailpipes to guide the sound into the car's cabin. Because The Akrapovic Evolution Line (Titanium) exhaust system has two valves, one more than the stock configuration, a TNG controller is included in the product to activate the additional exhaust valve. To make the sound experience even more unique, there are two tuned resonators – developed especially for this new engine – producing a deep, rich, and sporty sound with no unwanted drone or streaming, perfectly aligned with the straight six-cylinder engine. It weighs 21.7 kg, which is 23% lighter than stock. Power gains of 8.7 kW (11.8 hp) at 5,600 rpm and torque increases of 17.1 Nm at 4,100 rpm were recorded when tested on The Akrapovic dyno against a BMW M440i with a standard stock exhaust. Special parts are cast in The Akrapovic in-house foundry to create the intricate and complex items needed for this system. Meant for track use only and for non-OPF vehicles, remapping is recommended with this product.Please note that both product codes, S- BM/T/31H and E-BM/SS/8, have been split due to packaging reasons. Both codes must be ordered.Fitment notice: The Evolution Line (Titanium) only fits on non-OPF vehicles. For non-OPF vehicles, the ECE type approval certificate is not valid.An extra stock valve actuator (part nr. 18 30 8 686 640) is needed when installing the Slip-On exhaust system on BMW M340i (G20, G21) and M440i (G22, G23, G26). This product also fits on the BMW M440i xDrive Cabriolet (G23) model.THIS PRODUCT DOES NOT MEET EMISSION COMPLIANCE REQUIREMENTS FOR STREET OR HIGHWAY USE.