Porshe 911 GT3 RS 2015 review

Porsche's racer relishes the high-speed track work and is no slouch on the autobahn.

Porsche doesn't care if its new $387,700 racer for the road is overtaken on the autobahn. The maker will be upset, however, if the 911 GT3 RS is passed on a racetrack.

It's relatively simple to build something with a turbocharged monster motor and a very high top speed, says Andreas Preuninger, Porsche's high-performance car and motorsport director.

What's difficult is creating a road-legal car that can lap the Nurburgring in the blistering time of 7 minutes, 20 seconds. This is the best lap so far clocked by the 911 GT3 RS and means it's very, very unlikely to be overtaken by anything wearing numberplates.

Porsche didn't hire the Nurburgring for CarsGuide to try the 911 GT3 RS, which will go on sale here in August, but let us loose on Bilster Berg instead. This privately owned 4.2km circuit is much shorter than the fabled Ring but every bit as testing.

If Bilster Berg is a villain of a track, the 911 GT3 RS is the hero to conquer it

There are gut-churning blind bends over crests, curves in backside-squashing compression dips, corners where the slant of the road is just plain wrong and never a moment of rest for the driver.

If Bilster Berg is a villain of a track, the 911 GT3 RS is the hero to conquer it. This latest in a line of RS models stretching back a decade is the most extreme of them all. "RS" stands for Racing Sport at Porsche and the latest iteration puts more emphasis on the first word than any of its ancestors.

It eats Bilster Berg. The six-cylinder engine is a work of wailing, high-revving engineering art. It sings to 8800rpm before you must flick the double-clutch gearbox's paddle shifter to snap to the next gear.

Porsche claims a 0-100km/h acceleration time of just 3.3 seconds. This impressive number doesn't convey the supernatural precision with which it responds to the accelerator pedal or the blink-of-an-eye quick gearshifts.

The Porsche also grips as if you're driving on another planet, one with more gravity than mother Earth pressing its rubber against the bitumen. The rear tyres are huge, wrapped skin-tight in bodywork from the Turbo, widest 911 of them all.

The GT3 RS, like all 911s, packs its engine in the rear, so the front tyres, with less work to do and weight to bear, are narrower. The quick, electric-assisted steering makes them feel like extensions of your fingers.

At high speed, the RS's whopper rear wing and vented front guards develop serious downforce. Up to 345kg of it. Speed also produces extra power, ramming air into the Turbo-look intakes ahead of the rear wheels that are the engine's nostrils.

This is a truly, madly, deeply special car

This Porsche also gets rid of speed with the same ease it finds it. Especially with the expensive optional carbon ceramic brake discs fitted.

This is a truly, madly, deeply special car. Which is exactly what Porsche set out to create. Perhaps the only car to rival its power, precision, pace and purposefulness is the even more expensive Ferrari 458 Speciale.

As in the Ferrari, the engine uses revs instead of turbochargers to make big-time power. The 4.0-litre flat-six engine specially developed for this car produces 368kW (500 old-fashioned horsepower) at 8250rpm.

Porsche's PDK, a seven-speed double-clutch with a manual-shift mode, is the only transmission. Herr Preuninger knows some keen drivers prefer a manual but the stopwatches say this is a foolish choice. "One thing is for sure, the PDK is faster," he says. End of discussion.

Compared with the GT3, until now the most track-focused version of the 991 series (the current 911 family), the RS has wider axles, bodywork and tyres, less weight and more aero downforce. From nose to tail this Porsche is a no-expense-spared array of exotic materials and expert engineering.

The two-seat cabin isn't the stripped-bare environment of a V8 Supercar. It has aircon and a multimedia screen in its beautifully finished dashboard, for example. But then you notice telling details.

There are cars that might overtake this Porsche but the queue is very short

The steering wheel, 20mm less diameter than standard, is covered in grippy Alcantara. A slim yellow stripe shows the straight-ahead position, which racers like. The frames of the body-hugging leather and Alcantara trimmed seats are one-piece carbon-fibre shells, so there's no backrest adjustment.

The half rollcage fitted to test cars will be part of the Clubsport option package in Australia.

It comes as a huge surprise that this track-eating Porsche feels fine on German backroads outside Bilster Berg. Its suspension isn't uncomfortable and noise levels are reasonable until you give the engine wide-open throttle.

Hold pedal to the metal long enough on an autobahn and the 911 GT3 RS will run up to 310km/h.

There are cars that might overtake this Porsche but the queue is very short...

Magnesium makeover

The 911 GT3 RS is the first road-going production car in the world with a magnesium roof, claims Porsche.

Lighter even than carbon-fibre, this part shows how much trouble the company will take to shave a kilo from its track hero.

Magnesium sheet wide enough to make the roof is made in only one country in the world, South Korea. The metal is then stamped to shape in Canada and primed for painting in the US, before being shipped to Germany.

Other weight-saving parts, including carbon-fibre for the front guards, luggage compartment lid and rear wing, and plastic for the rear window and fixed side windows, come from a 500km radius around Porsche's factory at Zuffenhausen, near Stuttgart.

"This makes me very happy," says bodywork project manager Christoph Bauernfeind.

It probably pleases the company accountants, too.