Sensationally fast on road and track, Porsche's GT3 RS 4.0 is one of the most exciting cars, well, ever.
So, this really is it for the current, 997-generation of Porsche 911. Impossibly wide, hunkered down to the ground and looking every inch like a full-blown racer, the 4.0-litre version of the already hardcore GT3 RS is about as extreme a road car as you're likely to find.
Standing alongside it at Silverstone today - and, it has to be said, looking as pleased as punch - is Andreas Preuninger, who heads up Porsche's GT car programme and has played a role in every version of GT3 since the first one was launched in 1999. "Before we came along, 'GT3' was just the name of a class in racing. Now, if you search just for GT3 on Google it comes up with Porsche as third on the list - now it is associated with us," he beams.
The GT3 RS 4.0 follows on from the basic 997-generation 3.8-litre GT3 and GT3 RS road cars, throwing in some bits of the turbocharged GT2 RS road car and RSR race car for good measure. It's also the eighth and final GT3 that will use the M97 "Metzger" engine, which will make way for a direct injection unit for the next generation of 911 GT3.
And be in no doubt that this car is all about the engine. With no room to increase the bore (already at its limit at 102.4mm), Preuninger and his team instead worked on the stroke, which has gone from 76.4mm to 80.4mm. "To increase the stroke is not good for a high revving car usually," he says. "But this one was better because we changed a lot of other things. There are different rods and heads and we've lowered the compression ratio meaning you can use a more aggressive ignition curve."
A naturally-aspirated unit with 493bhp at 8,250rpm and 399lb ft of torque at 5,750rpm are the results of the fettling, which also includes swapping the GT3's standard crankshaft for the item from Porsche's RSR racer. Compared with a "standard" RS, those are gains of 50bhp and 22lb ft of torque, enough to knock a tenth off the car's 0-62mph acceleration time (now 3.9 seconds) and add 1mph to the top speed (193mph). That last figure might not seem particularly impressive given the extra grunt on tap, but that's because the 4.0 has more downforce than a regular RS. Much more.
"The 3.8 isn't a tractor engine," says Preuninger. "It's been maxed out for 10 years. Top speed is not important, it's about acceleration. This car has a nine-degree angle on the rear spoiler, whereas it's six degrees on the 3.8, so we have 195kg of downforce at top speed. Then we've put flics on the front bumper to balance out the extra rear downforce." He points to the small aerodynamic additions in the corners of the front bumper. Do they work? "In the Fuchsröhre at the Nürburgring with the flics on you can take it flat. Without them, you can't."
The result of such differences is that the RS 4.0 is six seconds faster around the Nordschleife than the RS 3.8, not to mention five seconds quicker than the Carrera GT supercar, with a lap time of 7min 27.
The attention to detail exercised to gain that extra power is matched by the focus placed on the 4.0's suspension, which gets a rose-jointed rear setup from the GT2 RS, as well as helper springs to reduce unsprung weight. Lightweight plastics (for the side windows and rear screen), plus carbon-fibre abound, while inside the changes include carpets that are half the thickness of a normal 911's. As a result of all the tinkering the RS 4.0's kerb weight is 1,360kg, a further 10-kilo reduction on the 3.8-litre RS.
Clearly this is a very special car, with just 600 being built and all already sold despite the £128,466 price tag being nearly double that of a basic 911. The question is, does the driving experience live up to the exotic specification?
In a word: yes. There was little doubt that the RS would be sensational around Silverstone, but just how ferociously it accelerates and just how stable it feels through corners is bordering on surreal. Miss an apex or brake too late and never do you get the sense that the RS might bite. Indeed, so composed is the chassis and so communicative are the major controls (this really is one of the best steering systems around) that you'll rarely see the traction or stability lights flashing, no matter how ham-fisted your driving.
It is the engine that steals the show, however. The first time you hit the reserves of mid-range torque your initial thought is that you must be a gear lower than you actually are. It's a clue that what you really need to do is approach every corner a gear higher than you're used to, and let the torque do the work.
Pick-up from 2,000rpm is strong and by 3,000rpm you're bordering on the mid-range shove offered by a 911 Turbo. That it then pulls hard all the way through to 8,500rpm shows that the work Preuninger and his team have done to maintain the flat-six's character has been a complete success. So fast is the RS 4.0 that it feels like it smashes through the 10mph increments between 130-160mph as easily as it does from 30-60mph. It really is epic.
What's always surprised about RS 911s is that the excellence they demonstrate on track doesn't translate to a car that's impossible to drive on the road. Get used to the heavy clutch and weighty, short throw of the six-speed gearbox and guiding the RS 4.0 through town traffic is no more intimidating than any other 911. And the ride quality, while firm, is certainly not unbearable, even on typical British B roads. In truth, if you can make do with noise (and there is quite a lot of it from the engine and tyres) it's almost as satisfying to drive on the road as it is on track.
So, despite its serious track car credentials, the GT3 RS 4.0 is no one-trick pony. Rather, it's a first class road and track car, not to mention a fine investment for the lucky 600 who had their names down for one.
The best car of 2011 so far? It might just be.
THE FACTS : Porsche GT3 RS 4.0
Tested: 3,996cc naturally aspirated flat-six engine, six-speed manual transmission, rear-wheel drive
Price/on sale: £128,466/sold out
Power/torque: 493bhp @ 8,250rpm/ 339lb ft @ 5,750rpm
Top speed: 193mph
Acceleration: 0-62mph in 3.9sec
Fuel economy: 20.1mpg (EU Combined)
CO2 emissions: 326g/km
VED band: M (£1,000 first year, £460 thereafter)
Verdict: Sensational. Costs nearly twice as much as an entry-level 911 and worth every penny
Telegraph rating: 5/5 stars
