Spy Shots: Next-gen Porsche 911 sporting double-bubble roof

With every iteration of the 911, Porsche makes incremental improvements to its iconic sports car and naturally, the next generation will be no exception.

This latest 911 prototype was caught at the Nurburgring sporting 997 sheetmetal, but it's what's on top and out back that deserves note. A double-bubble roof panel has been fitted, while underneath the rear camouflage is a sizeable wing and additional ducting. Look closely and you'll see a small sill at the base of the rear windscreen that's assumed to be feeding the rear-mounted flat-six – likely necessary keep the boxer cool while Porsche engineers figure out how the new contoured roof affects aerodynamics. If previous reports are to be believed, we can expect the next 911 to debut sometime in 2010, but we wouldn't rule out an appearance at the Frankfurt Motor Show this September.