Compared to the 997, the 991 is slightly larger, with the wheelbase increased by 100 mm (3.9 in) to 2,450 mm (96.5 in), and the overall length up by 70 mm (2.8 in) to 4,490 mm (176.8 in).
A new transaxle was developed so that the rear wheels could be moved 76 mm (3 in) backward in relation to the position of the engine, which significantly improves the weight distribution and cornering performance of the car.

Due to the use of high-strength steel, aluminium and some composites, the weight was reduced to 1,380 kg (3,042 lb) for the manual Carrera, rising to 1,605 kg (3,538 lb) for the all wheel drive Turbo model with PDK transmission (Porsche Doppelkupplung).
PDK is available as an option for all 911 Carrera models as a 7-speed transmission, featuring manual and automatic modes.
Gears 1 to 6 have a sports ratio and top speed is reached in 6th gear.
7th gear has a long ratio and helps to reduce fuel consumption by keeping engine revs low.
The PDK is essentially two gearboxes merged into a single unit and thus requires two clutches.
For all 991 models, the PDK is produced by ZF Friedrichshafen.
The auto start/stop function is standard on all variants of the 911 Carrera.
Compared to the 997, the 991 is slightly larger, with the wheelbase increased by 100 mm (3.9 in) to 2,450 mm (96.5 in), and the overall length up by 70 mm (2.8 in) to 4,490 mm (176.8 in). A new transaxle was developed so that the rear wheels could be moved 76 mm (3 in) backward in relation to the position of the engine, which significantly improves the weight distribution and cornering performance of the car.
Due to the use of high-strength steel, aluminium and some composites, the weight was reduced to 1,380 kg (3,042 lb) for the manual Carrera, rising to 1,605 kg (3,538 lb) for the all wheel drive Turbo model with PDK transmission (Porsche Doppelkupplung). PDK is available as an option for all 911 Carrera models as a 7-speed transmission, featuring manual and automatic modes. Gears 1 to 6 have a sports ratio and top speed is reached in 6th gear. 7th gear has a long ratio and helps to reduce fuel consumption by keeping engine revs low. The PDK is essentially two gearboxes merged into a single unit and thus requires two clutches. For all 991 models, the PDK is produced by ZF Friedrichshafen. The auto start/stop function is standard on all variants of the 911 Carrera.
Porsche 991