The strange thing is that engineers have fitted a full roll cage inside this luxury automobile. This is something you do when you're going to take the car out on the Nurburgring. The fact that it was being escorted around by a 911 Turbo indicates this is indeed the case?
One possibility is that this caged beast is a test vehicle for the Panamera junior sedan, the Pajun as it's been dubbed. It's a bit too elaborate for a mule though. We'd also suggest this could be the Turbo S, since the 2014 model range has inexplicably stopped at the Turbo.
That's just a shot in the dark though, which means the Porsche mystery box is half full.