Milltek BMW 4 Series F82/83 M4 Coupe/Convertible (Non-OPF equipped models only) 2014-2018 Secondary Catalyst Bypass Exhaust F33 440i The problem is especially pronounced

The problem is especially pronounced under hard braking

the X34 Carbon Fiber Intake System offers discerning enthusiasts measurable increases in horsepower and torque

DI 4 Digital Input for switching functions

but when the revs rise and the valves open

Milltek BMW 4 Series F82/83 M4 Coupe/Convertible (Non-OPF equipped models only) 2014-2018 Secondary Catalyst Bypass Exhaust F33 440i The problem is especially pronouncedAll Milltek performance exhaust systems are manufactured from T304L stainless steel; giving you the satisfaction of knowing that our products are meant to last within some of the toughest environments. T304L is a highly durable form of stainless steel that is far less susceptible to degradation and discolouration than many others of its kind, while it will last almost indefinitely.