It's been about a year since the facelifted first-generation Panamera arrived in U.S. dealerships for the 2014 model year, and Porsche is already working on a successor for its sports sedan. Sure, rumors of a redesigned Panamera->ke1840 have been flying around since early 2014, but it is only in late September that the actual vehicle was spotted in the wild. Of course, the Panamera depicted above is still an early prototype, but the lenses of our skilled paparazzi caught a few interesting features that are new to this four-door sports car->ke506.

Details are still under wraps, and the powertrain lineup remains a well-guarded secret, but that's not exactly surprising considering the second-generation Panamera is nearly three years away. We expect the new sedan->ke142 to make its official appearance in 2017, and go on sale in the United States for the 2018 model year. We also expect to bring you numerous details on the new Panamera by the end of 2014. Meanwhile, read on to find out what we know so far.

Click past the jump to read more about the next generation Porsche Panamera.

Spy Shots

Although the mule is cleverly camouflaged to look like the current model, there are a few details that reveal it's a brand-new car. The most notable change is at the rear, where a different tailgate design is obvious. Also, the rear section appears to be slightly longer, while the roof seems to carry a slightly different shape. Another photo we received in our inbox tells us Porsche has modified the Panamera's rear spoiler as well. The piece has a larger surface area and ditched the split design we're all familiar with from the first-generation car. You can also spot a new sunroof on its roof.

Other changes are less visible on this prototype, but expect to see new front and rear bumpers, revised side skirts, as well as new headlamps and taillights.

The new Panamera also gets a new platform. Porsche's state-of-the-art platform, dubbed MSB, will make the sedan significantly lighter and stiffer, enhancing the car's performance while reducing fuel consumption and CO2 emissions.

There's no word as to what engines will be offered with the second-gen Panamera, but word has it the Germans are working on new V-6 and V-8 powerplants with twin-turbo technology. An updated hybrid drivetrain is also in the works, and we also expect to see a four-cylinder unit in an entry-level model destined for the European and Chinese markets.

2014 Porsche Panamera