Downpipe dedicated to the M57 engine mounted on: BMW E39 525D BMW E39 530D Downpipe diameter: 2.5 "(63mm) Outlet diameter: 2" (51mm) Mounting flange: Original TurboWorks downpipe, made of 100% stainless steel. to M57 engine mounted in: BMW E39 525D BMW E39 530D Downpipe diameter: 2,5 "(63mm) Outlet diameter: 2" (51mm) Flange: OriginalTurboWorks downpipe, made 100% of stainless steel.Downpipe designed for M57 engine installed in: BMW E39 525D BMW E39 530D Downpipe diameter: 2.5 "(63mm) Outlet diameter: 2" (51mm) Mounting flange: Original TurboWorks Downpipe, made of 100% stainless steel.