Of course if you're a 911 fanboy you'll likely already know all about the GT3 RS 4.0. But, even if you've got the necessary £128,466 there's some bad news. They're already sold. All 600 of them. Of that number our contact at Porsche was somewhat vague on how many would be coming to the UK, eventually conceding it would be "around one per Porsche centre" but "less than 10% of the overall production run." So that'll be a number greater than 32 but fewer than 60 then.
No, the GT3 RS 4.0 is about details. Details resulting in the famous 'Mezger ' engine's capacity creeping up 200cc to make it the biggest ever fitted to a roadgoing 911 and boosting power over the regular GT3 RS from 450hp to 500hp and torque from 317lb ft to 339lb ft. The 4.0's additional aero - nine degrees of rear wing over the RS's six and front bumper mounted 'flics' to reduce resulting front-end lift - mean top speed is only 1mph up at 193mph and 0-62mph down a tenth to 3.9 seconds. But what was that about meaningless stats? The changes to the 4.0 can be better appreciated in just one corner on Silverstone's International Circuit.
Preuninger admits the 3.8 RS's flat six is "not a tractor engine" but by increasing the stroke - there was literally not enough metal in the block for any increase in bore - with the same crank as used in the half million pound RSR race car they wrung out those final few hp and lb ft. New heads, cams and shorter, wider inlet tracts also play their part in the astonishing 125hp per litre specific output. Oh, and if you're worried about durability part of the test programme was running flat out for 3,000km at Nardo.
Like the GT2 RS, the 4.0 gets additional rose joints on the suspension arms and uprated coilovers with compensator springs to allow a shorter, lighter main spring. None of this fancy pants hardware can overcome those inherent 911 handling quirks though and the 4.0 still has that 'will it, won't it' light-nosed feel on turn-in that, assuming you've not totally overlooked the additional speed you arrived with (see above), can be bled off with a little bit of trail braking. The fierceness with which the engine responds has you wary of being too early on the power but, inevitably, even when you think you're being brave you're actually being a wuss and everyone will know about it, so loud is the exhaust when you're on properly on it. Dig deeper and the response is so accurate, the communication so undiluted that you can actually feel the differential begin to lock up and fire you out of the corner for that classic 911 slingshot effect.
Again it's the engine that dominates, the rate with which revs and speed build requiring serious mental recalibration. Like all 'proper' Porsches this is a car that makes demands of its driver and assumes a certain level of competence before giving its best. There's no Ferrari style ego massage here.
And though the stickers, plank-like rear wing, roll cage and aero flics mark you out as a bit of a tragic wannabe away from the track from the driver's seat you won't mind. Because, like the regular RS, the 4.0 is surprisingly viable as a road car. A road car that doubles, trebles even, speed limits in the blink of an eye admittedly. But it rides well, bumps, cambers and ridges clearly communicated via wheel and seat of the pants but the feedback so clear and faithful it's never intimidating.