The German sportscar company has taken the can opener to its flagship 911 Turbo with two new super-fast soft-top models.

Destined for their first official public appearance at the LA Auto Show, which opens its doors on November 20, Porsche promises that the soft-top versions of its 911 Turbo and Turbo S will not be adversely affected by the reduced rigidity and increased weight that come from removing their roofs.

The standard Turbo will be able to accelerate from zero to 100 km/h (62 mph) in 3.5 seconds and on to a top speed of 317 km/h (197mph) while the Turbo S is infinitesimally quicker off the mark (3.2 seconds to go from zero to 100km/h) but has the same top speed. And of course, Porsche being Porsche is focused on how the performance compares to the outgoing Turbo convertibles — 15 percent greater fuel efficiency, 30hp more on tap and 0.2 seconds shaved off the 0-100kph time — than to how the new cars measure up to their coupe versions.

With so much power on tap and with the added distraction of having the roof down, even the most committed driver is going to need some help keeping one of these convertibles on the straight and narrow, or in ensuring that a power slide doesn’t become a power skid into the nearby flora and fauna, so the same active four-wheel drive and equally active aerodynamic systems found on the standard Turbo model have thankfully been carried over to the soft tops, as has Porsche’s dual-clutch paddle operated transmission.

Meanwhile to make sure that the driver and passengers don’t get caught out by a sudden change in meteorological conditions, the electrically operated roof can be raised or lowered in 13 seconds and while the car is traveling at speeds of up to 50km/h (30mph).

In the US, the cars will be priced at $160,700 (Turbo) and $193,900 (Turbo S) when they go on sale in early 2014, whereas Europeans will only have to wait until Christmas. The cars will go on sale officially in December and will cost £126,766 for the ‘entry level’ Turbo, £149,511 for the Turbo S Cabriolet (around €175,000 and €210,000).