These new Porsche models will be launched at the Detroit Motor Show in January.
The new open-air 911 comes with a choice of either the 239 kW 3.6-litre flat-six or the S-model with its 3.8-litre power unit developing 261 kW.
As on the coupé versions, Porsche has once again enlarged the range of standard equipment.
The new convertibles are equipped with features such as larger wheels, a wind deflector, PSM Porsche Stability Management and PCM Porsche Communication Management including Porsche Sound Package Plus (CD radio with nine loudspeakers).
The car benefits from outstanding lightweight concepts, the basic version weighs a mere 1480 kg (Carrera S: 1505 kg), thus ranking right at the top in its market segment. Both cabriolets weigh just 85 kilos more than their respective coupé counterparts.
Porsche claims that as a result of their good power-to-weight ratio and that typical Porsche suspension, these two open-air sports cars offer "exemplary agility and dynamic handling particularly in bends".
The Carrera S cabriolet comes as standard with PASM Porsche Active Suspension Management available as an option on the 3.6-litre Carrera and offering an entirely new dimension in driving dynamics.
Both models have exactly the same top speed as their coupé counterparts ? 285 km/h and, respectively, 293 km/h.
The 3.6-litre version of the open-air Carrera (with manual gearbox) accelerates to 100 km/h in 5.2 seconds, the Carrera S Cabriolet completing this exercise even faster in 4.9 seconds.
The soft roof opens and closes fully automatically at the touch of a button in just 20 seconds.