Porsche brought back it’s much loved flat-6 engine in the 718 but it only came in a package suited strongly for the track. Want that smoothness, punchiness, and throaty engine note with a dollop of comfort and civility? That would be the GTS 4.0. Available in both 718 Boxster and Cayman models, it gives up nothing for the driver that wants a good romp on a country backroad.  Tom Voelk tests a well optioned Boxster that retails for $117K. You didn’t think it would be inexpensive did you?