Carlos Lago tests the wonderfully capable Panamera 4S. This year Porsche replaced the naturally aspirated 4.8-liter V-8 in the standard and S model Panameras with a twin-turbo 3.0-liter V-6 (the GTS retains the V-8). This new engine makes more power and torque than the outgoing one and returns better fuel economy, but does it have the same excitement as the V-8? We find out by exploring the always impressive performance limits of this luxury sedan.