A Billet Resonator Plug and Billet PCV Re-Route Plug will allow you to not only remove the 6.6L Resonator Box that resides on the top of your engine, but also allows you to the PCV in a sleek manner to clean up the appearance of your engine bay. This will eliminate the crank case exhaust from being vented back into the intake side of the motor, causing soot and oil to build up which can cause a loss of performance, decreased fuel mileage, and loss of horsepower.