Porsche has been caught testing the next-generation Porsche Cayman S out on the track in Germany. The new car will be built upon the upcoming Porsche Boxster platform and feature grown-up proportions as well as a possible flat four-cylinder turbo engine.

It seems the next Porsche Cayman will be slightly more filled out compared with the current model, even stretching into the size of the current Porsche 911 in some areas.

The front seems to exhibit more pronounced front guards and wheel wells, featuring a higher arch peak like a 911. The rear appears to be longer as well while the roof line is carried down at an angle similar to the 911's.

The rear window and the wheelbase is also said to be fractionally larger than the current model which could indicate a larger, more practical interior, particularly at the rear.

Like the upcoming Porsche Boxster, the Cayman is rumoured to feature the company's new flat-four engine in the entry-level model. Reports say a 2.5-litre four-cylinder turbocharged boxer unit might be on the cards producing upwards of 260kW.

The 2012 Porsche Cayman is expected to go on sale sometime next year after an official unveiling beforehand. We'll keep you updated.