McLaren Merc gets the go-faster treatment

The McLaren Mercedes SLR isn't exactly an obvious candidate for a performance upgrade, but since when has logic dictated terms in the rarified world of supercars?

Witness the Stuttgart/Woking mob's latest concoction: the Mercedes-Benz SLR 722 Edition, a steroid-injected riposte to those Italian upstarts -- specifically, Ferrari's 599GTB and Lamborghini's Murcielago LP640.

The limited-edition McMerc builds on the strengths of the already bonkers 'base model' by hiking power and introducing more hard-core brake/suspension specification.

Raw numbers suggest the silver bullet has the Eyties covered. Power climbs from an already muscular 460kW to a T-shirt-ripping 478kW -- strangely enough (not), this is sufficient to pip the 599GTB (462kW) and Murcielago LP640 (470kW).

The 722 Edition's supercharged 5.5-litre V8 is hand-built in the AMG skunkworks in Affalterbach and the manufacturer boasts that it offers "immediate response to movements of the accelerator, highly emphatic torque build-up and an unmistakable V8 sound".

We couldn't have put it better ourselves. Well, actually, we could.

Not surprisingly, the acceleration figures being claimed put the British-German car in the butt-cheek-clenching category. The 0-100km/h increment is dispatched in a disdainful 3.6 seconds, while the double-ton flashes past in just 10.2 seconds.

For what it's worth, v-max also rises from the unfettled car's 334km/h to 337km/h -- not quite up there with the Bugatti Veyron, but quick nonetheless.

Other upgrades to complement the added 'phwoar' include stiffer suspension that lowers ride height by 10mm and larger brake discs that measure a garbage-can-lid-approximating 390mm in diameter.

Trainspotters will notice the modified front spoiler with air splitter, as well as the rear diffuser. These tweaks are claimed to improve aerodynamic efficiency and provide added downforce at high speeds.

Sports seats upholstered in leather/Alcantara are said to provide outstanding lateral support, while the grippier racing steering wheel, gearshift paddles and black carbon highlights lend a "thoroughbred racing touch to the interior".

In case you're wondering about the '722 Edition' moniker, it's all to do with history as the ultra-low-volume coupe pays homage to the 1955 Mille Miglia triumph of Stirling Moss and Dennis Jenkinson in a Mercedes-Benz 300 SLR. Their starting number was 722 (indicating a start time of 7:22am).

The SLR 722 Edition went on sale in Europe on July 11, and customers and "selected guests" had the opportunity to appraise the car at a special event to mark the foundation of the worldwide 'SLR Club' at the Circuit Paul Ricard in Le Castellet, southern France.

As an ultra-exclusive community of which SLR customers automatically become members, the SLR Club is said to provide "an attractive platform for outstanding events related to the SLR, as well as numerous other benefits".

The club also has an 'SLR Safety & Speed Academy', which offers special driver training courses and seminars conducted by the likes of  David Coulthard, Jochen Mass, Klaus Ludwig, Chris Goodwin and Christina Surer.