K&N Performance Intake Ford Focus ST 2013-2014
K&N's 57S Performance Airboxes increase horsepower and acceleration by dramatically reducing air flow restriction caused by the original factory design. They come with K&N's Million-Mile Limited Warranty. 57S series airboxes replace the factory air filter housing with a fully enclosed injection modified airbox containing a reusable K&N air filter. Installation is easy as they are specifically engineered to use factory holes and mounting points. No additional hardware, cutting or drilling is required.