For owners of 2003-2004 Mach 1 vehicles, this system is designed to replace everything in front of the factory mass airflow system. It comes complete with MAF adapter, Conical air filter assembly and custom filter cover designed to retain the function of the original shaker assembly used on the Mach 1. Performance is maximized by keeping the filter directly in front of the air meter housing, protecting the filter with the custom shield assembly and drawing the colder air in from the fenderwell and shaker simultaneously. This setup is superior to simply replacing your stock filter with a K&N, as the physical size of the factory replacement filter does not provide enough capacity to maximize the horsepower gain from the filter upgrade. On these vehicles, the typical horsepower gain to be expected is about 6-7 at the rear wheels. For an additional improvement, and to greatly enhance the underhood appearance of the Mach 1 vehicle, you can add our aluminum Trueflow inlet pipe (part #713) to replace the large (and ugly) rubber inlet hose that runs between the mass airflow unit and throttle body