Open overdose: The new Porsche 911 Turbo Cabriolet

It's hard to believe that the turbopowered icon from Zuffenhausen turned 40 this year. Coinciding with this important birthday, the Los Angeles Auto Show in November will see the new open-topped versions of the 911 Turbo and 911 Turbo S make their global debut.

The two Turbo Cabriolets follow closely in the technical footsteps of their coupé equivalents, including the 3.8-litre 6-cylinder engine with either 520HP or – in the S model – 560HP. The 0-62mph sprint takes 3.5 and 3.2 seconds respectively, beating the two models' predecessors by a small but (at these performance levels) significant 0.2 seconds. Top speed is around 198mph (318 km/h) and both cars boast innovative rear-axle steering. 

They are also visually similar to the coupé versions when the roof is closed (a process that takes 13 seconds at speeds up to about 30mph), with a coupé-like arch to the roof thanks to Porsche's 'panel bow top' that uses a lightweight magnesium frame.

However, the clear similarity to the coupé doesn't conceal the fact that - to us - the open version of the fabulous Turbo sports car seems a bit of an overdose. If you really feel you need to go topless, it will cost you a hefty premium over the coupé, too - with prices in Germany set at 174,431 Euros for the 'standard' Cabriolet, and 207,989 for the Turbo S.

Photos: Porsche

You can find plenty of modern and classic Porsche 911 Turbo Cabriolets in the Classic Driver Market.