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 (x) F32 / F33 BMW 428i (x) F32 / F33 / F36 Replacement for OEM BMW Part# 18327645666 from year of construction 10/2012+ made out of high quality stainless steel 1.4301 (SS304) 100% perfect fit, replace OEM less thermal load on the turbocharger more power by reducing back pressure significantly more torque without catalytic converter connection diameter 105mm *ECU will need to be coded to avoid engine management light errors.