We've got the kit for your 2 or 4-valve 4.6L Mustang. This package features a brand new 80mm housing, conical K&N Filter and a plastic shield to cover the filter and hold the assembly in place. Through extensive testing on our DynoJet dynamometer, we have found consistently excellent results. On a 2-valve model horsepower increases by fourteen with a solid average of ten more horsepower by 3000 RPM to redline. The 4-valve model also benefits from the deeper breathing of this package adding a minimum of eleven horsepower with a peak of sixteen more horsepower. These results were achieved on a vehicle that was equipped with a K&N filter in their factory airbox assembly.