Porsche Panamera in its technical glory

Porsche's new Panamera four-door is due to be officially unveiled in Shanghai next month (April 2009), but Yahoo! Cars got early access to Porsche's new machine at its test facility in Weissach, Germany. The first thing to get out of the way is its looks: the Panamera is not as ungainly in the metal as the pictures suggest. Forget about the styling though, as the Panamera is all about being the fastest, most agile four-seater around and it's loaded with new technology to achieve that.

From launch there will be three different Panamera models: the rear-wheel drive Panamera S, the four-wheel drive Panamera 4S and the Panamera Turbo. It's a sign of our ever more environmentally conscious times that with the Panamera Porsche isn't just focussing on the sort of performance you measure with a stopwatch, but also heavily on its environmental responsibilities.

The first car to be offered with a stop-start system in conjunction with an automatic transmission, the Panamera's V8 engine shuts down to save fuel when you're stopped at the lights or in congested traffic. Starting again instantly when you push the accelerator, this, along with Porsche's quest to keep the Panamera's weight down and low-rolling resistance tyres, helps the Panamera S return an official combined cycle of 26.2mpg and CO₂ emissions of 253g/km, bettering the sub-20mpg figures offered by most of its key rivals. That's for a car that's able to reach 62mph in 5.2 seconds. Even the Panamera Turbo, with its ability to reach 62mph in just four seconds returns 23.2mpg and 286g/km.

The stop-start system isn't the only new technology Porsche is debuting on the Panamera. The new car can cosset like a traditional luxury saloon and react like a sports car thanks to a new development of its Porsche Active Suspension Management (PASM). The system uses air springs that have the ability to change their volume to enable the Panamera to fulfil both roles, its sporting ability further enhanced by a limited-slip differential on the rear axle and PDCC, which provides active anti-roll bars.

Aerodynamics help the Panamera in its economy quest, Porsche managing the airflow around the car with a flat underside and active spoilers at the rear to increase stability and reduce drag. Customers will be able to experience how the Panamera's new technology helps make it one of the most remarkable four-seat sports cars ever from September this year, with prices starting at £72,266. Having sat alongside one of Porsche's test drivers in the new car we can assure you that they won't be disappointed, the Panamera certain to cause serious upset to the performance saloon marketplace among its AMG and BMW M Car rivals.

Kyle Fortune