Porsche Panamera

Porsche CEO Matthias Mueller admits that "there certainly were doubts" when the first Panamera launched in 2009. Critics didn't like the hunchback styling and were skeptical whether a sedan fit the Porsche brand. Yet in the four years since, Panamera sales have outpaced Porsche's predictions by 25 percent. Based on that success, it's no wonder Porsche made only small changes for the Panamera's first facelift.

Identifying the visual tweaks is as tough as a spot-the-difference puzzle. From the front, look for headlights that are rounded rather than angular, a revised "power dome" hood bulge, a flatter fascia, reshaped lower air intakes, new side skirts, and relocated LED running lights. Wholesale bi-xenon headlights become standard with full-LED illumination optional. Drivers in slower cars will note new taillights, a different fascia that places the license plate lower and visually widens the rump, a wider and flatter rear window, and a minutely changed curvature to the roofline.

More extensive changes await beneath the skin, beginning with a new plug-in hybrid model called the S E-Hybrid. It replaces the S Hybrid, which currently accounts for about ten percent of all Panamera sales, and announces itself with acid green brake calipers, badges, and gauge needles. A 9.4-kWh lithium-ion battery stores a greater charge than the old car's nickel metal-hydride unit; although the new pack is the same size as before, it weighs 110 pounds more. Better windings and magnets in the drive motor allow Porsche to use a higher voltage and boost electric-drive power to 95 hp and 229 lb-ft, increases of 49 hp and 8 lb-ft compared to the outgoing version. The 3.0-liter supercharged V-6 engine and eight-speed automatic transmission are mostly unchanged, the former producing 333 hp and 325 lb-ft. When the motor and engine work together, they can knock off a 5.2-second 0-to-60-mph time and reach a 168-mph top speed.

The improved motor and battery mean drivers will be able to go a claimed 20 miles on battery power alone. They also should produce better fuel economy ratings than the 2013 S Hybrid's 22/30 mpg (city/highway). We averaged an indicated 2.2 L/100km over about 30 miles of mixed driving, equivalent to an astonishing 107 mpg, but only because the majority of those miles were covered in E-Power mode with the engine switched off.

Recharging the Panamera's battery from a 120-volt outlet will take at least four hours, or just 2.5 hours if you use a 240-volt charger. Unlike most other plug-in hybrids, however, the Porsche can fully recharge its battery on the move. Pushing the E-Charge button diverts some of the engine's power to rejuvenate the battery, although it somewhat numbs throttle response and impacts overall economy. But it's designed so that you could, for instance, recharge on a long highway journey in order to drive electrically on the urban streets at your destination. We still managed 6.7 L/100km (35 mpg) in E-Charge mode, an impressive figure for a car with a combined 416 hp and a curb weight of 4619 pounds. The battery pack was also fully recharged after about 35 miles of driving with E-Charge enabled.

The trade-off for all this efficiency is less refinement than in other Panameras. Because the electric motor drives through the eight-speed automatic, it changes gears where other plug-in cars simply accelerate smoothly in a single "gear." The gasoline engine thrums and moans, especially in E-Charge mode, and the automatic transmission never shifts as sweetly as the PDK dual-clutch in other Panameras. Fortunately, the brakes feel natural and the hand-off between regenerative and mechanical braking is almost impossible to discern. Acceleration is still brisk when running only on battery power, although the car's top speed is reduced to 84 mph.