BMW X3M X4M FRONT MOUNT SILICONE INTAKES S58Description Front Mounted Silicone Intakes for the 2020+ X3M and X4M. 3. 5" (88mm) inside diameter wherever possible, and stepping up to 97mm internal diameter (110mm OD) in the longer stretches. The hoses are wire reinforced so they will retain shape and never collapse. We used the best air filter option we could find on these. Unlike some other intakes on the market, the air filters will never be a restriction for these intakes. The sound from the