Stuttgart, Germany - The Porsche Panamera scheduled for European showrooms in March 2009 has been spotted during testing with spy shots revealing more details of the sleek four-door sedan.

Built on the same chassis as the Cayenne, the Panamera is powered by either a 3.6-litre V6 with 300 hp from Volkswagen or the 4.8-litre V8 with 350 hp also found in the Cayenne.

Spy shots published by Germany's auto-motor-sport magazine reveal a rear wing providing downforce and a bigger rear window than in previous spy shots. The bonnet is more contoured and the headlights are clearly visible.

Porsche is also planning to offer the Panamera in a hybrid version at a later stage. It will be based on the hybrid technology revealed in a Cayenne Hybrid prototype. It is fitted with a V6 engine combined with an electric motor positioned between the engine and the gearbox, according to auto-motor-sport. (dpa)