A while back, Shelby introduced the Carroll Shelby Signature Edition package for the Ford Mustang. The bundle turned the regular Mustang GT into a more aggressive pony design-wise and replaced the standard V-8 with a supercharged unit capable of 825 horsepower. Now, Shelby is extending the Signature Edition to the GT350 and GT500 models. These new packages are much thinner on the performance front, but they're also notably more affordable. The Signature Edition is available on the 2020 Shelby GT500 and 2015-to-2020 Shelby GT350 models, including the GT350R. Like all Shelby conversions, every Signature Edition car will receive a Shelby CSM number and will be documented in the official Shelby American Registry.