Ford Performance today reveals the all-new Mustang Dark Horse R, offering the most demanding track enthusiasts a turn-key race car ready to compete in the all-new Mustang Challenge spec racing series, just for Mustang Dark Horse R and sanctioned by the International Motor Sports Association (IMSA). The Mustang Dark Horse R powered by a new, fourth-generation 5.0-liter Coyote V8 is the third Dark Horse-based racing derivative to be unveiled this summer, joining its place alongside the Mustang GT3 and Mustang GT4.