Invisible revolution: the 991 series marked a new stage in the history of the Porsche 911 evolution. The improvements, although perhaps not too obvious, were still many and targeted. Appeared at the Frankfurt Motor Show 2011, the 991 series immediately received critical acclaim. The Turbo version, however, only arrived in 2013; as had happened with the 997, the supercharged version was available in two versions: Turbo (3.8 liters, 520 horsepower) and Turbo S (same engine but 580 horsepower). In 2014 it was the turn of the convertible bodies. Over the years, and especially with phase II, the turbos underwent a slow but constant evolution, with the 911 Turbo also gaining twenty bhp.