The GT3 has shared core engine components with the 911 GT3 RSR racer since its creation in 1999, ­making it the rare machine that can honestly be described as a race car for the road. But the 2014 GT3 doesn’t use the RSR’s “Mezger” flat-six, named after Hans Mezger, the career Porsche engineer famous for designing possibly the ultimate air-cooled automobile engine, the mighty 917’s flat-12. During development in the 1990s, the 996’s new water-cooled engine was deemed unfit for racing, so the motorsports department continued to improve the original 911’s flat-six, favoring its dry sump and stout bottom end. Porsche would finance this work, in part, by selling that engine in 911 Turbos, GT2s, and GT3s. The Mezger mill, already water cooled for racing applications, became a symbol of superiority for its owners, boasting brand heritage and a motorsports pedigree that added to the GT3’s mythology. The Mezger is a staple of Porsche lore, but its link to the GT3 has been broken by the steady march of technology—or, more specifically, direct injection and the PDK transmission. Though the GT3 Cup and RSR race cars soldier on with the storied engine, the new roadgoing GT3 is powered by a derivative of the Carrera S six.