K&N Performance Air Intake Kit 63-2578 with Lifetime Red Oiled Filter for 2011-2014 Ford Mustang GT 5.0L V8 Estimated horsepower gain of 20.27 HP at 5400 RPM Designed to improve throttle response and engine sound Easy to install, usually in 90 minutes or less Great looking and light weight carbon fiber heat shield Not legal for highway use in states adopting California emission regulations