Joining its custom Focus ST at the 2013 Detroit Auto Show this week was Shelby American’s new wide-body kit for the Ford Mustang, which the company previewed on its flagship GT500 Super Snake.

Shelby also used the Detroit show to unveil a wide-body version of the GT500 Super Snake wide body. Shelby fans will recall that in 1986 Carroll Shelby worked his magic on the Dodge Omni GLH ...