The production version of the 918 Spyder hybrid – first seen in concept form at the 2010 Geneva Motor Show – went on sale from this week. The two-seater roadster, inspired by the design of the Carrera GT and the 917, is built around a carbonfibre-reinforced plastic monococque structure and has manually-removable roof panels which can be stored in the front luggage compartment.

The 918 Spyder features Porsche’s 493bhp V8 engine, a mid-mounted high-revving unit developed from that of the racing RS Spyder, a winner of the Michelin Green X Challenge in the American Le Mans Series, the Le Mans Series and the 24 Hours of Le Mans. This engine’s power is supplemented by a further 215bhp from a pair of electric motors.

Power is delivered to the rear wheels via the seven-speed PDK (Porsche double-clutch) gearbox, with the electric motors driving the front wheels for an all-wheel drive set-up. Lithium-ion batteries allow for an all-electric driving range of over 16 miles, and they can be charged from a standard domestic power socket.

Combined fuel consumption is an estimated 94mpg, with carbon dioxide emissions of just 70g/km – yet the 918 Spyder can accelerate 0-62mph in just 3.2 seconds and reach a top speed of 199mph (94mph, in all-electric mode). It’s capable of lapping the Nürburgring Nordschleife in less than seven minutes and 30 seconds – quicker than the Porsche Carrera GT.

Porsche is to make just 918 examples of the 918 Spyder, and production will start on 18th September (9/18, in US dating convention), 2013. First deliveries will begin November 2013 at a price tag of €615,000 (approx. £537,000).

Buy one and Porsche will throw in a special edition 911..

Well that’s not quite true, Porsche would never just ‘give away’ a 911, even if you had just paid half a million pounds for a 918 Spyder, but the company is offering 918 Spyder buyers a further exclusive option: the chance to order a limited-edition 911 Turbo S ‘Edition 918 Spyder’ coupe or cabriolet, featuring similar design cues to their beloved 918, such as the acid green-trimmed upholstery, instrument needles and door entry guards.

Each of these 911s will have the same production number as the 918 Spyder ordered by the customer, and can be ordered in the same colour; just 918 of these are available as well, and deliveries will start in June 2011.