Recent spy shots have indicated that Porsche has been working on an updated version of its Panamera. But while the German automaker is waiting until later this month to reveal the updated model in Shanghai, some initial details and photos have emerged early. The new Panamera incorporates upgraded styling, including new lights and bumpers front and rear, a reshaped tailgate and relocated license plate frame, but the real juicy details center under the hood.

The refreshed Panamera will be available with a new gasoline-electric powertrain that's claimed to propel the Panamera S E-Hybrid to 91 mpg (on the European cycle, anyway) and below 100 g/km of CO2 emissions. The hybrid powertrain pairs a 316hp 3.0-liter V6 with a 94hp electric motor and 9.4wWh lithium-ion battery pack, as previewed by the Sport Turismo concept unveiled at the Paris Auto Show last September. That makes it significantly more efficient and powerful than the outgoing hybrid, and sends it to 60 in just 5.5 seconds and on to a 167mph top speed - in a hybrid sedan.

In non-hybrid models, a new 3.0-liter twin-turbo V6 is replacing the 4.8-liter V8 in the Panamera S and 4S, providing 413 horsepower (19 more than the V8) and 385 lb-ft of torque (14 more), while reducing weight ion the nose and fuel consumption by 18%. No word on modifications to the base, diesel or turbo models, but we're expecting further details in the coming days and weeks as the Shanghai Auto Show approaches, so watch this space.