Check out the latest spy shots of Porsche's upcoming 911 Turbo.

Porsche's latest 911 Turbo is still a few months away from its official unveiling, but an eagle-eyed Leftlane reader has sent us images of what appears to be the next-generation of the Porsche flagship undergoing testing in Germany.

Spotted on the open roads of Germany's Autobahn, the prototype in question is clearly based on the current 991 generation of the Porsche 911. However, the mystery car sports a few styling cues not yet seen on the newest 911, leading us to believe this could be a prototype for the upcoming 911 Turbo.

The biggest clue hinting at a turbocharged flat-six beneath the rear end of this test car is the presence of large air inlets just in front of the rear wheels. A signature design cue of recent 911 Turbo models, the extra venting is likely required to feed the turbocharged flat-six hanging out the back of this prototype. We've heard early estimates that the 991 911 Turbo could crank out as much as 530 horsepower by way of a triple turbo setup.

Another tip off to this car's identity is its large rear wing out back. Needed to keep all that power to the ground, 911 Turbo models have historically used larger fixed wings while lesser models have relied on retractable units.

Lastly, the prototype's exhaust is the telltale sign of a turbocharged Porsche. Although a relatively new design cue, a similar quad-exhaust setup is used on the Panamera Turbo. The new-look exhaust system is apparently becoming a staple of Porsche's top-level passenger cars, much like Audi's use of oval exhaust pipes for its RS models.

There is still no official word on when we will see the 991-based 911 Turbo, but the car could bow sometime next year as a 2014 model.