The design of both cars closely follows the recently introduced 911 Turbo and Turbo S coupes, while boasting a unique body that is 28mm wider than the widest of the current 991-generation models, the Carrera 4.
The new models also feature a signature rear wing that deploys for additional downforce at speeds above 120km/h.
Another update is a retractable fabric roof with a lightweight magnesium frame. The roof opens and stows in a dedicated compartment behind the rear seats in around 13 seconds at speeds of up to 50km/h.
Just like its fixed-roof siblings, the 911 Turbo Cabriolet uses a newly developed turbocharged version of Porsche’s 3.8-litre flat six, developing 383kW/660Nm and 412kW/700Nm in the S model.
It has a seven-speed PDK dual-clutch transmission and all-wheel drive, with increased traction by an electronically controlled torque vectoring system for the rear wheels.
Porsche claims the new 911 Turbo Cabriolet and 911 Turbo S Cabriolet will sprint from 0-100km/h in 3.5sec and 3.2sec respectively, making the new-generation cars 0.2 seconds faster, while being 15 per cent more efficient.
Both versions are capable of hitting a top speed of 318km/h, while on the combined cycle use 9.9L/100km and emit 231 g/km of CO2.
The interior of the new Cabriolet model follows that of the 911 Turbo Coupe, boasting a particularly extensive range of features including adaptive sports seats with 18-way adjustment and memory, backrest shells trimmed in leather with double cap seams and various carbonfibre accents.
A two-tone Black/Carrera red interior is also available as a no-cost option.
Bose audio is standard, but for the first time a Burmester system is available on request. Also optional is the radar-controlled adaptive cruise control, camera-based road sign and speed limit recognition function and reversing camera.
The new range-topping 911 Cabriolet models are now on sale in Australia priced from $388,800 and $463,100 respectively, with customer deliveries commencing towards late April 2014.