Porsche has taken the wraps off the fastest Panamera Sport Turismo model yet, the Turbo S E-Hybrid.

It is powered by the 550hp turbocharged V8 motor found in the Panamera but is paired with a plug-in hybrid powertrain that features a 14.1kWh lithium-ion battery pack and an electric motor producing 136hp. The total output of the Panamera Sport Turismo Turbo S E-Hybrid is 680hp and 850Nm of peak torque from just 1,400rpm.

The combined output is sent to all-four-wheels via an eight-speed automatic transmission that helps the estate to hit 100kph from standstill in a claimed 3.4sec, which is 1.4sec quicker than the regular E-Hybrid Panamera. Porsche further claims a 0-198kph time of 11.9sec, a top speed of 310kph and a fuel efficiency of 33.33kpl.

The 14.1kWh lithium-ion battery can be recharged in 2.4 to six hours depending on the power outlet. The range-topping Panamera hybrid also has a 49km pure-electric range and a top speed limited to 140kph.

The addition of the battery back has seen boot space shrink by 95 litres with total boot space at 425 litres, which can be expanded to 1,295 litres thanks to the rear seatbacks that can be folded electrically in a 40:20:40 split.

As standard, the Sport Turismo Turbo S E-Hybrid comes with 21-inch alloy wheels, Porsche Dynamic Chassis Control and torque vectoring. There’s also a rear, limited-slip differential and ceramic composite brakes, as well as adaptive three-chamber air suspension with Porsche Active Suspension Management.

The Turbo S E-Hybrid is the new range-topping Panamera variant and will rival the likes of the Audi RS6 Performance and Mercedes-AMG CLS 63 Shooting Brake in international markets.

Also see: 2017 Porsche Panamera Turbo review, test drive