We’ve known for a while that the MP4-12C was just the warning shot at McLaren’s declaration of war against established supercar manufacturers. In fact, we have already detailed its plans for a new range of supercars based on the carbonfiber chassis of the MP4-12C.

The open-top version of the McLaren MP4-12C will be the first one to hit the market and battle it out with the new Ferrari 458 Spider .

British motoring magazine Car reports that McLaren has already manufactured a prototype of the MP4-12C Spyder with the production version scheduled to be revealed before the end of this year. It is based on the coupe and will be powered by the same 600HP, 3.8-liter twin-turbocharged V8.

Unlike its nemesis from Maranello, though, chopping off the roof doesn’t come at the expense of replacing the glass engine cover with a non-transparent hood since McLaren’s engineers have lowered the plenum by 8 mm, thus keeping the powertrain visible.

Car says that according to sources close to the project, the MP4-12C Spyder will feature a three-piece roof made of aluminum and plastic and, like the 458, its design will be more like a targa than a full convertible due to the buttresses behind the seats that also act as rollover hoops.

The same sources claim that roof operation takes around 17 seconds, 3 more than the Ferrari, and can be lowered or raised at speeds up to 5 mph (8 km/h).

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