Akrapovic BMW F30 340i & F32 440i OPF/GPF Evolution Exhaust Link Pipe SetThe Akrapovic exhaust evolution link pipe set for the BMW 340i and 440i upgrades the Slip On system to the Evolution system. The Evolution link pipe set is constructed from high quality austenitic stainless steel. It features an arrangement of two central link pipes, which replace the single pipe stock design for the best flow of exhaust gases from the engine. It is designed to increase power and torque and reduce overall weight, while delivering a