The 2020 Ford Mustang Shelby GT500 is the most powerful Mustang to leave the factory, but Shelby American couldn't leave a car that carries its name alone. That's the basis for the GT500 Signature Edition, which adds even more power to the supercharged 5.2-liter V8 and a host of exterior and interior modifications. The most important part of the GT500SE is under the hood, and thanks to a new heat exchanger, intercooler, and ECU adjustments, a total of more than 800 horsepower is on tap versus 760 for the "base" GT500. A new dry carbon fiber hood with aggressive louvers and iconic Shelby stripes and badges set it apart outside. Wider tires, sway bars, springs, and recalibrated suspension settings improve handling, while the interior gets recovered seats in leather with a not-so-subtle snakeskin pattern. The GT500SE package will run about $30,000 on top of a stock GT500.