Sunday marked the conclusion of the 2014 North American International Auto Show in Detroit, the 14-day automotive extravaganza that hosted a bevy of noteworthy reveals from the world’s leading luxury marques. For its part, Porsche unveiled the 2014 911 Targa, the latest in its line of roll-bar-equipped convertibles that originally debuted in 1965. The inclusion of a roll bar—or Targa bar, as Porsche calls it—increases the stiffness of the car’s chassis, which translates to better handling during sharp tur…