1: Basic brake rotor. 2: Grooved rotor - the grooves give more bite and thus more friction as they pass between the brake pads They also allow gas to vent from between the pads and the rotor. 3: Grooved, drilled rotor - the drilled holes again give more bite, but also allow air currents (eddies) to blow through the brake disc to assist cooling and ventilating gas. 4: Dual ventilated rotors - same as before but now with two rotors instead of one, and with vanes in between them to generate a vortex which will cool the rotors even further whilst trying to actually 'suck' any gas away from the pads.
An important note about drilled rotors: Drilled rotors are typically only found (and to be used on) race cars. The drilling weakens the rotors and typically results in microfractures to the rotor. On race cars this isn't a problem - the brakes are changed after each race or weekend. But on a road car, this can eventually lead to brake rotor failure - this would be A Bad Thing. This is worth menthioning only because of a lot of performance suppliers will supply drilled rotors for street cars without mentioning this little fact.
Certain cars require more upgrading for brakes than others. Mustangs happen to be one of those vehicles. AmericanMuscle does a great job and how to go about upgrading from the stock form.
Wiper Motor Rotor, Auto Parts, Rotor for Car Wiper Motor manufacturer / supplier in China, offering Rotor for Car Wiper Motor, 450mm Wiper Blade (LC-WB1002), CE Approved Windshield Wiper Motor for Light Truck (LC-ZD1006) and so on.