For the original manual-only Aston Martin V12 Vantage, launched in 2010 (as a 2011 model), the British marque stuffed its largest engine into its smallest body. Flash forward three years and the model has become a cult favorite among serious driving enthusiasts. For the 2015 model year, the Aston Martin V12 Vantage S Roadster draws more power from the naturally aspirated 6-liter engine—565 hp and 457 ft lbs of torque—and is available with a folding soft top. However (and perhaps sadly to some), the manual gear…