With the Mercedes SLR McLaren Roadster hitting the end of the road next year, it’s being milked as much as possible. Roll in the 722 S, billed as the ultimate edition of the super sportscar.

Delivering 478kW, acceleration from 0 to 100km/h in 3.7 seconds and a maximum speed of 335km/h, this two-seater cabriolet surpasses the existing benchmark of the SLR McLaren Roadster. In addition to increased power, the new 722 S features more dynamic suspension tuning and improved aerodynamics. But it's limited to 150 vehicles.

By naming this new model variant the SLRRoadster 722 S, Mercedes-Benz is recalling the historic victory won at the classic Mille Miglia long-distance race in 1955 by British motor-racing legend Stirling Moss and his co-driver Dennis Jenkinson, in a Mercedes-Benz 300 SLR with the starting number 722.

The heart of the 722 S is a supercharged 5.5-litre V8 engine which is hand-built in the Mercedes-AMG engine shop. With the 478kW output and 820Nm of torque, figures exceed the SLR McLaren Roadster's 460kW and 780Nm.

The five-speed automatic transmission developed by Mercedes-Benz is designed for high performance. It is specially configured for a very high torque, and allows the driver to choose between two sets of shift characteristics. As a result, apart from the sub-4 second 0 to 100km/h time, 200 km/h is reached in 10.6 seconds. The maximum speed is unrivalled by any other series-production roadster.

The spring and shock absorber configurations of the suspension are stiffer, and the body has been lowered by 10mm at the front and rear. This ensures the greater handling stability, with a significant improvement in handling dynamics. The lightweight, 19-inch forged aluminium wheels allow a view of the red-painted brake callipers on the carbon-fibre/ceramic brake discs.

The qualities of the 722 S are complemented by the fully recessible fabric soft top, which blends into the flowing lines of the roadster. The weave structure of this roof material reflects the carbon-fibre look and allows the vehicle a top speed of 335km/h — an unusual figure for a roadster. Thanks to favourable aeroacoustics, conversation during open-air journeys is still possible at well over 200 km/h.

The soft top opens and closes semi-automatically in around ten seconds. For opening, the roof needs to be unlatched at the windscreen frame and lifted slightly, after which it folds down electrically. The front section of the soft top features an integral aluminium cap, which effectively prevents "ballooning" at high speeds.

The handling and aerodynamics of this high-end roadster were optimised for high speeds in the wind tunnel. The aerodynamic concept follows that of the SLR Coupé, with an airbrake integrated into the boot lid, an enclosed underbody and a diffuser in the rear bumper to ensure the greatest possible downforce on the rear axle. The so-called airsplitter at the front end augments this downforce, while small wheel spoilers reduce turbulence at the rear axle. The result is precise handling and steering at high speeds.

In technical terms the 722 S benefits from the long experience of Mercedes-Benz and its F1 partner McLaren. With the exception of two aluminium frames, the body is completely of carbon-fibre materials (CFRP). Especially for the roadster, the sophisticated carbon-fibre technology was developed further for the monocoque. The result is low weight, superior energy absorption and therefore a high level of occupant safety, plus a torsional rigidity unprecedented for an open-top car.

A high level of safety is provided by unique carbon-fibre crash structures, steel-reinforced A-pillars and two fixed rollover bars. Other safety features include adaptive airbags, knee and sidebags, belt tensioners and a tyre pressure monitoring system.

The roadster has a crystal antimony grey paint finish, which highlights the sculptured look. The carbon-fibre technology is visually complemented by the black, grid-like air vents on the bonnet and the front and rear light modules with palladium grey surrounds.

In the interior, lateral support is guaranteed by sports bucket seats upholstered in a combination of semi-aniline leather/Alcantara. Visual highlights are provided by the contrasting seams in 300 SL red, the embossed 722 S lettering on the head restraints and the likewise red seat belts. Frequently used controls such as the shift and parking brake levers are lined in particularly high-grip and moisture-absorbing suede leather. In the interior too, the use of carbon-fibre underlines the high-performance philosophy.

Exclusive appointments include two-zone automatic climate control, a high-quality BOSE Premium sound system, a multifunction sports steering wheel with shift paddles and a navigation system with an integrated radio and CD player.

This limited edition of 150 examples is predominantly hand-built at the Formula 1 workshops of McLaren in Woking, England, and is available from 1 January 2009.