It weighs 1370kg to DIN standard (70kg lighter than the already pared-down GT2), and just 1280kg 'dry' - only 80kg more than the naturally aspirated GT3 Cup competition car. That DIN figure includes 30kg of coolant alone. It has 453hp per ton, and 377lb ft per ton, the peak of the latter is available from just 2250rpm all the way to 5500rpm. It's interesting to do the same maths with some rivals...
So, extraordinary numbers, and they certainly make entertaining reading, but they don't fully relate the human story of this project, or tell the complete picture of how the car actually drives. The latter, in some respects, is something of a surprise.
When Rohrl recorded a 7m32 at the 'Ring in the GT2 during the spring of 2007, there was another car tucked away in the garage which the engineers suggested he might like to try for himself. Typically, Rohrl jumped at the chance and clocked 7m29 on his first lap in 'Lighty': all the ammo Preuninger needed to approach the board with his proposal.
But this car then saves further weight in the body through polycarbonate rear side glass, a beautifully made carbon fibre bonnet (a 2.5kg saving over the aluminium one), and front wings made from carbon fibre, with the wheel arch extensions now part of the mould (unlike with the GT3 RS). In fact there are carbon fibre parts all over the car now, especially inside the cooling apertures.
Continuing through the car, 10kg was shed from the suspension components, with a number of bits now being manufactured from aluminium. The GT2 RS has 'linear' rate springs on the rear axle in conjunction with small helper springs that combined weigh less than the usual 'progressive rate' items.
One of the key objectives during the development process was moving up to a 245-section front tyre (from 235 on the GT3 RS), which caused all sorts to packaging problems for a while including wheel-well rubbing at the Foxhole on the 'Ring. But the gain has been a 10 per cent increase in the side force generated, and while it was impossible to go any larger than the already massive 325-section rears, the rear suspension now uses various rose joints to more precisely locate elements of the rear suspension.
Meanwhile, Preuninger and his team had been cajoling the engine department to find even more power and the output kept on rising. The new engine features larger, more efficient intercoolers, a new lightweight plastic intake system and stronger conrods so it can cope with 1.6 Bar of boost pressure, passing the full range of temperature and durability tests like any new Porsche as it does so.
What I'm about to say might sound incredibly tedious, but what initially strikes you about the GT2 RS is just how easy and pleasant it is to drive. After all the talk of numbers, it's a shock to discover that it rides so well - better than a Carrera blighted by the Sport suspension 'upgrade' - and that the controls, thanks to their lightness of touch and precision, are so easy to work with in normal driving. The car feels so alert and biddable, you find yourself wishing all 911 Turbos would drive like this.
Fourth gear is particularly amusing: because the peak torque is so low you can be trundling along in traffic and just stretch your big toe to get past vehicles in a superbike fashion. And then you can just leave it in that gear until you're at silly three-figure numbers. It's like a bizarre automatic 'box. One speed.
At £167,915 the GT2 RS looks like something of a performance bargain relative to its peers, but of those with that kind of money to spend some will quite legitimately baulk at the lack of a charismatic 8, 10 or 12 pot wail, a low, supercar silhouette that stops pedestrians in their tracks and a beautiful interior. And although it's entirely academic, I suspect there'll be plenty of people who might recoil in horror at spending the price of a new Carrera over that of the awesome GT3 RS: they'd miss that car's manic raw aggression too, its immediate throttle response, lofty rev limit and heavenly soundtrack.
On that last point Walter Rohrl has the last word in response to a question, from me (delivered with stupid grin and suitable reverence): "Is it a bit interesting in the wet then, Walter?"
The answer, from Walter (with a similarly exaggerated face of fear to the one he used moments earlier when we were chatting about the 1981 Silverstone 1000kms: driving a monster of a 935 with an experimental 800bhp motor, in the rain, he won, while going mostly sideways): "Ja...you can be sure..."
3,600cc, twin turbocharged (VTG) flat six,
620hp at 6,500rpm
516lb ft from 2,250-5,500rpm
Weight (DIN/wet) 1,370kg
245/35 ZR19 (front)
325/30 ZR19 (rear)
Top speed: 205mph
Combined fuel figure: 23.7mpg
CO2: 284 g/km