Wagner Tuning 57mm Charge Pipe Kit BMW M2/M3/M4 S5557mm (2,25 Inch) Charge Pipe Kit for BMW F87 M2 Competition F80 M3 F82 F83 M4 with S55 Engine Product features: compared to the OEM Charge Pipes, the WAGNER system has a larger flow diameter and minimal internal cross sectional changes, unlike found in the OEM product this results in 40% less back pressure, which relieves the turbocharger and at the same time ensures better response behaviour (see Flow Bench graphic below) our WAGNER Charge Pipes are