With winter closing in, trust Porsche to give us something bright to look forward to.

The 911 Turbo Cabriolet has been unveiled now ready for a December launch. OK, with a price well into six figures, you would be a very lucky motoring to get one of these for Christmas.

But it certainly looks like being the best Porsche open-topper for a while. Its arrival will crown quite a year for the marque, coming as it does after the Which? consumer magazine praised its customer satisfaction and reliability.

Every year, the annual Which? Car Survey asks the question: ”who makes the best cars?”.

And for the second year in a row, the influential publication has rated Porsche the ‘Best Car Brand’ in the UK.

Based on the assessment of more than 57,000 vehicles up to eight years old, the magazine concludes: “Topping the standings for the second year in a row, the addition of the new 911 to the ratings has done the Stuttgart-based manufacturer no harm.

“Reliability for cars over three years old is decent, and owners who can afford to buy one are fanatical about their worth, giving the brand a 94 per cent customer score. Upcoming test scores for the latest Boxster and Cayman are expected to further bolster this strong showing.”

But back to the 911. The flagship 911 Turbo and Turbo S Coupe models are now joined by Cabriolet versions which will get their official unveiling at the Los Angeles Motor Show in November. UK prices are £126,766 for the Turbo Cabriolet and £149,511 for the Turbo S Cabriolet.

In true Porsche form, these highly-engineered cars are more than just seductive lookers. A Porsche spokesman said: “The dynamic capabilities of the new 911 Turbo models combined with the driving pleasure offered by an open-top sports car.

“This is the compelling formula behind two new flagship 911 Cabriolet models. Some 50 years after the 911 first appeared and to coincide with the 40th anniversary of the 911 Turbo, Cabriolet versions of this iconic model are making their global debut.”

The pair will be unveiled to the public for the first time at the Auto Show in Los Angeles on Wednesday, November 20.

The 911 Turbo Cabriolet and 911 Turbo S Cabriolet deliver the same blend of dynamism, performance and efficiency offered by the Coupe model unveiled just a few months ago.

The turbocharged 3.8 litre six-cylinder engine delivers 520bhp in the open-top 911 Turbo and 560bhp in the S model.

The cars accelerate from 0 to 62mph in 3.5 and 3.2 seconds respectively, reaching a top speed of up to 197mph. And all this while achieving fuel consumption figures not typically associated with such high performance.

Both new models return 28.5mpg on an average route with CO2 emissions of 231g/km. When compared against their respective predecessors, the new cars deliver 30bhp more power and are 0.2 seconds faster to 62mph acceleration. They are also up to 15 per cent more efficient.

As ever, there is plenty for petrolheads to get excited about. The active rear-axle steering and active aerodynamics, for example, lead to better ride and handling.

While the rear-axle steering has a beneficial impact on handling for the two new models – both on the racetrack and during everyday use – the active aerodynamics can be tuned to offer optimum efficiency or driving dynamics at the touch of a button.

More than ever before, both of these new models also make a visual statement about their performance.

The widely-flared rear wings of the new 911 Turbo generation are broader than those of the 911 Carrera 4 models.

And to keep them secure, each car comes with a Porsche Vehicle Tracking System (VTS).