For the past two years at the Tuner Grand Prix at Hockenheim, the most ferocious, 650bhp GT2s have been sent home with their tale between their legs by a car with more than 200bhp less. That machine was the flagship GT3 RSC, the road-legal racing car featured in the sidebar, with works Porsche driver Marc Basseng at the wheel. It has gone on to form an integral part of the brand and this, the Carrera S Cabriolet-based Cargraphic GT3 RSC 3.8 is the latest in the lineage. It makes a wholesome 404bhp with a few carefully chosen mods, and a handles like a knife.

Cargraphic specialise in slicing understeer from the base set-up to produce a pin-sharp nose that turns in like a razor and lets the driver decide what happens with the rear. They can do power upgrades to 650bhp and beyond with the 911 Turbo, but a holistic approach with a real emphasis on handling and dynamics, rather than monumental power boosts, have long been their calling card.

This car comes with Power Kit 2, which takes it all the way to 404bhp and 449Nm of torque. Cargraphic gets a sports exhaust, with a high-flow trimetal catalytic set. That feeds a sport backbox with twin tailpipes 89mm internal rolls leading to the central exhaust outlet. RS Tuning do the engine mapping, hence the credit in the name and they find the horses throughout the range. It hits 62mph in 4.8s and tops out at 190mph - just shy of the Turbo's terminal velocity. Cargraphic has fitted a short shift kit to the gearbox and a Bilstein suspension set-up that drops the front end 35mm on to massive 20" centre-lock wheels. Yet to its credit, the car feels as finger light as Zuffenhausen's Carrera. The gears still slot simply home with a nudge, rather than a shove and the RSC could comfortably cover hundreds of miles and is nothing like the ragged edge experience on offer elsewhere.

Of course it's loud, and Cargraphic have one of the sweetest sounding kits on the market right now as every rev seems to reverberate round the can like an angry swarm of something dangerous. With the hood down, one arm on the window and soaking up the German sunshine and appreciative looks from the local girls it felt no harder to helm than a standard 911.

Stay away from the limits and it's an every day car. PASM works in harmony with the kit and in comfort mode it transmits real ruts and major traumas in the road a little harder than Porsche's Ride and Handling team might have liked, but it's still not enough to intrude. The team have done a masterful job of setting up sharp-handling suspension that didn't try to break teeth, even on the railway line running straight through the centre of town. Unless you've grown accustomed to the cosseting Carrera suspension, the difference would be nigh-on impossible to spot without the PASM dropped to Sports setting.

It's easy to see the sporting intent from the outside, though, as the orange RS-style graphics liberally applied to the substantial bodykit are attention-grabbing, although I'd be tempted to go for a pure black version. A GT3-style front bumper with a visible carbon-fibre vent frame comes married to a carbon-fibre lip spoiler that might need replacing now and again but looks stunning with the lip curling round to the sides to give the front end a touch of snarling aggression. A few squared off edges have taken the marshmellow-styling approach of the base model to bits. The door mirrors come covered in more carbon-fibre and then there's a whole rear bumper assembly to convert the Carrera's squat-look to the more muscular GT3 assembly. And they've topped it all off with another blade of carbon-fibre that boasts a seductive quality in the flesh thanks to its perfect finish and fit.

This was all skin-deep, though. After driving through the town, though, we came to a winding road through a vineyard that serves as one of Cargraphic's favourite test roads. Of course the Nordschleife is not far away, but this road has all the ingredients: crumbling, varied surfaces, off-camber bends and a straight that will support acceleration up to fifth gear and serious speed. And only there did the true core of this machine come through, this is no cosmetic makeover. Cargraphic have reached deep within the car and a few deft touches have transformed the lightweight of the 911 line-up into a keen, sporting contender. Racing up to 140mph before a heavy braking zone showed a rev counter that was almost too eager to spin up and it was simply a case of keeping track with the six-speed gearbox and landing it back in the sweet spot for the constant surge of power. And with the added acoustic power of the exhaust buzzing through the open air it feels even quicker.

The suspension kit is backed up by a carbon-fibre strut brace and while this can't compensate for the extra weight in the cabin compared to a real GT3, this car still feels keener thanks to a sharper set-up on the nose and that all-round height drop. With the lightweight, forged 'Star' alloys covered in 8.5x20" Michelin Pilot Sports on the front and 12x20" on the rear there's a serious amount of mechanical grip, too. And apart from a couple of splitter scraping moments when turning the car around on slopes it was perfectly composed over bumps and furrows, a soar in revs indicating a wheel had let go for just a microsecond was the only indication of the car working so hard. With more grip and less of the understeer that Porsche dials in to the Carrera S as a straightforward safety measure, it inevitably hangs on much harder in the bends and will take in quite outrageous speeds through the bend as long as the driver is smooth and precise. Get cocky, switch off the electrics and push too hard on the entry to the bend, though, and the back end will step out and arc through the bend with less encouragement than you'd perhaps expect.

The answer is obvious: leave all the gadgets on and the car will keep the racing car edge without any of the associated consequences, but switch them off and you'd better be sure you can drive a car with such honed reflexes. As you just might have to. Under those spindly centre-lock alloys a standard Porsche steel disc and calliper is plain to see, yet the keener set-up keeps it stable under heavy braking and this car would take lumps out of the standard Carrera on the middle pedal, in the corners, and more or less everywhere else. And when you're in the mood, dropping the suspension to its hardest setting and flipping off the car's own interference can turn this soft-hearted, sweet Cabriolet into the kind of girl you'd be afraid to introduce to your family.

Gallery: WCF Test Drive: Cargraphic GT3 RSC

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