Focus MK4 ST 90mm Group-A induction kitOur full no compromise induction kit for the MK4 Focus ST is now available to order. We would have used a smaller pipe. We could have used a smaller filter etc but where is the fun in that!! This 90mm mandrel bent aluminium pipe replaces the original Ford plastic pipe. Not only does it lift the appearance of the engine bay, it also smooths out the airflow and has an increased diameter to maximise the volume of air being forced into the engine to aid