The 991 GT3 already debuted at Geneva this year and Porsche wanted to split the two cars up for maximum exposure. The 991 Turbo in the photos has center locking wheels just like the 991 GT3. If the new turbo is anything like the new GT3 it will be lighter while having more power. A 3.8 liter direct injected motor sharing similarities with the GT3 as it will be built on the same production line will be incorporated.
Horsepower in the 530-550 range out of the 3.8 liter should be standard being sent to all four wheels by a 7-speed PDK transmission. Will the 991 Turbo lose the manual option like the 991 GT3 did? Unlikely as this is a higher volume car without the hardcore focus of the GT3.
Enjoy the spyphotos, more info should be coming soon and it just seems like Porsche will leak this car early themselves since September is so far away.