The Downpipe-Kit fits in to the n20 engine: BMW 125i F20 / F21 BMW 220i F22 / F23 BMW 228i F22 / F23 BMW 320i (x) F30 / F31 / F34 BMW 328i (x) F30 / F31 / F34 BMW 420i F32 / F33 BMW 428i (x) F32 / F33 / F36 Replacement for OEM BMW Part# 18327645666 from year of construction 10/2012+ High quality stainless steel  1.4301 (SS304) CAD-Designed without main catalyst* 2 Lambda probe connections 100% perfect fit, replacing OEM Less thermal load on the turbocharger Significantly more torque and power from reduced back pressure Connection diameter 105mm Exhaust diameter 76mm *Off-road use only unless catalyst fitted in exhaust mid-section. Removal of all catalytic converters will almost invariably make your vehicle illegal for use on a public road. ECU will need to be coded to avoid engine management light errors.