Charge Motion plates are located between our intake & our heads. Each runner has a butterfly in it. At a certain rpm (or tps voltage, I'm not sure), these butterflies open up. There purpose is for emissions and fuel tumble mixture at low rpms/low speeds. Even at wide open, the shaft that these butterflies are rived to is a restriction and causes turbulence.
Charge Motion Delete plates completely remove these butterflies and the shaft that they are riveted to. You're basically bolting in a dummy plate that has never had the shaft or butterflies installed to begin with.
For under $100, it's a VERY great mod. Even if it's your first time installing these, the job can be done in 1 hour tops. If you get a tune from a reputable tuner, you will NOT lose any low end power. Also, I did not lose ANY gas mileage either. I'm sure if you put a sniffer on it, the idle emissions would *probably* be higher, but you can't smell anything. The difference is negligible as to what we can see, although probably a small tolerance for a manufacturer like Ford to meet CAFE standards.