Road Tests

2018 Porsche 911 GT3 vs. 2018 Mercedes-AMG GT R: Love at First Slide

A two-day, 600-mile tour de force in two of Germany’s top super sports cars

Autobahn at last! As the speed limit lifts and the road ahead clears, the 2018 Porsche 911 GT3 is out front of the 2018 Mercedes-AMG GT R when the day’s first give ’em stick moment arrives. Though the curves meander leisurely through the oldest stretch of the A92 motorway between Munich and the foothills of the Bavarian Forest, reading the road ahead is essential at 150-plus mph as heaves and off-camber sections often present themselves without warning.

Decked out in its resplendent Green Hell bodysuit, the voluptuous AMG GT R transforms into a twin-turbo thunderball as it reels in the winged 911. The big bad Benz has 577 horsepower under its loooong hood versus the GT3’s 500 hp, which explains why it’s getting the better of this impromptu high-speed duel. But the driver of the Guards Red 911 GT3 couldn’t care less. With the throttle pinned to the floor, he is totally engulfed in his own mind-boggling stratosphere, celebrating each blaring 9,000 rpm redline upshift with a spiritual thumbs-up and a smile.

To get the measure of these two supersonic German super sports cars, we set out on a two day, dawn-to-dusk test run that included lengthy flat-out stints, tasty stretches of Austrian back roads, climbs and descents packed with curves of all shapes and sizes, and syrupy city crawling. We topped it all off with an hour long, flat-out fun at the Wachauring racetrack near Melk, Austria.

Both cars have street cred in abundance. Mighty rear wings, big wheels, and widebody stances make no pretentions about their sporting intentions. The front end of the GT R looks particularly intimidating thanks in large part to its mean sharktooth grille, though its curved, stubby rear almost seems to belong to a different vehicle. Porsche has cleaned up the nose of its latest GT3, which deserves the extra-cost lift system to protect its protruding, rubber-lipped chin. In addition to their identical 198 mph top speeds, both cars can whiz from 0 to 60 mph in less than four seconds and have nearly identical fuel economy numbers.

Helping the new Porsche 911 GT3 go-faster are a battalion of high-tech advancements including rear-wheel steering, adjustable dampers, bigger tires (245/35 ZR20 front, 305/30 ZR20 rear), active engine mounts, and sophisticated electronics. Blessed with 20 percent more downforce than before, the red coupe is (and feels!) substantially narrower and trimmer than its mean green rival. The PDK-equipped GT3 we chose for this shootout is also roughly 275 pounds lighter than the GT R. Add to this the shorter wheelbase and overhangs plus a 40/60 front/rear weight distribution and it doesn’t take a genius to figure out the Porsche is one chuckable piece of kit.

As we meander east towards Vienna, loosely following the river Danube on a mixed set of byways, the differences between the two cars begin to manifest themselves. Despite its slightly more compliant suspension, the Porsche struggles to relax, let go, drop revs. Instead, it is totally committed at all times, noisily picking up and tumble-flushing loose chippings through the echo-chamber wheelhouses, celebrating an aggressively informative low-speed ride, letting the manly intake rasp and the dense exhaust rumble do most of the talking. In the GT R, full throttle acceleration maneuvers are accompanied by rolling acoustic earthquakes that come and go in waves – accentuated by fake heeling and toeing throttle blips and chip-generated lift-off backfires.

In the rolling hills of the Viennese hinterland, on the far side of the busy commuter belt, we pull out all the stops. Traction? Advantage Porsche, which can put all its weight and energy on its hind legs at all times. Turn in? A dead heat, at least in the dry, when the front tires bite until the entry speed is simply too silly for public roads. Mid-range grunt? Advantage GT R. With 516 lb-ft on tap from 1,900 all the way to 5,500 rpm, the torque tsunami from AMG’s potent 4.0-liter twin-turbo V-8 more than neutralizes the extra 2,000 rpm the Porsche driver can squeeze out of the GT3’s 4.0-liter, naturally aspirated boxer engine.

While the AMG is liable to wriggle its tail before ESP quickly catches it, 911s have been known to either understeer into oblivion or oversteer tail first into the ditch. The GT3 mitigates this inherent vice by offering a function called paddle neutral, which disconnects the rear wheels from the drivetrain the instant both shift paddles are pulled. The device does work, but first you must remember it exists, and then do what you’ve never done before. At any rate, fast cornering is all about torque management and steering balance. The level of tactility is commendably high no matter which helm you grab.

Quick response is of the essence whenever ample oomph meets dubious grip, and as soon as the fireworks start it doesn’t really matter whether the engine sits closer to the front or rear wheels. Through the open bends which snake up and down the Danube valley, it’s a little easier to kick the more frivolous GT R into play mode than the staunch 911, thanks in part to its multi-mode traction control device which harbors eight stages of drama, from mild to wild.

The geometric buttons in the center console of the GT3 invite you to turn up the exhaust volume, adjust the shock absorber calibration, speed up the drivetrain response, and deactivate ESP either on its own or together with ASR. It’s a straightforward ergonomic arrangement – no drive mode selector, no tweaking of springs and steering, no personalized mix-and-match program. In classic GT tradition, this is a not a blended 911 like the turbo S but rather a bartender’s selection served straight up, no chaser. For the 2018 GT3, Porsche’s GT car ringmaster Andy Preuninger has opted for a slightly more accessible setup with fewer rough edges. It adds up to a package that’s still totally involving yet charmingly viceless.

In contrast to the almost austere driver environment favored by Porsche, the AMG is a true luxo-sport machine and pragmatically practical daily driver with a bouquet of driver assisting modern conveniences. This is a Mercedes-Benz as much as it is a bespoke AMG creation. Cabin space is snug, but the trunk is easily accessible with roughly double the cargo room of its opponent. Like the GT3, the GT R also comes with unheated, body-hugging racing buckets adjustable solely in reach.

By lunchtime on day two, the autobahn stints had sucked two tankfuls dry. A concerted attack on the twisties coated the wheels with thick layers of furry brake dust, while our cornering adventures shaved off rubber all round. The tight alleyways in the old part of Vienna kept threatening the rims and the Merc’s all-embracing wing mirrors, but thankfully to no avail.

Last but not least – the track. We were lucky to get access to the Wachauring, a demanding circuit that with the exception of a second-gear corner at the end of its start-finish straight is all third and fourth-gear stuff.

A midday shower pushes the grip level on the track to high risk. Add to that cold tires and the marbles framing the racing line and our naked ambitions quickly give way to caution. Thankfully the skies clear and we head out in the AMG first to set the pace. What an awesome pace it is! Do not underestimate this car: Its massive, ventilated and cross-drilled discs, special compound Michelin tires (275/30 ZR19, 325/30 ZR20), trick suspension, electronically controlled limited-slip diff, and a variable-rate steering which even takes g-force into consideration add up to a scintillating dynamic package.

Once the tires are warm we zoom in on the limit by tightening the line, straddling the curbs here and there and stretching the friendship with the braking points. Turn-in is reassuringly positive now, torque begs to be fed earlier and earlier, and soon enough the right hand is once more reaching for that magic yellow traction control turning knob. There is no doubt about it: While the very first AMG GT was little more than a potent poseur, the GT R is competent and rewarding tool on the track or the road.

Over to you, GT3. Stepping from the world of AMG into the Porsche orbit is like entering a different universe which happens to be spinning at a near-identical speed. There’s pupil-widening understeer on the slippery approach to a dropping left-hander, but a brief pull at both shift paddles interrupts the push from behind, making the front tires rebound at once with the tarmac while encouraging rear-wheel steering to tighten the arc.

Look at it from whichever angle you like – there is no clear winner here. The GT3 is the smaller and lighter car. It lays power down with authority and defies the g-force long and hard. But, alas, it cannot pull away from its opponent. Hop back in the GT R and you’ll be just as fast if not a touch faster, and despite a completely different means of fusing acceleration and adhesion, even sharper steering and readily available excess horsepower and torque make the Swabian muscle car an equally exciting drive.

2018 Mercedes-AMG GT R Specifications

ON SALE Summer 2017
PRICE $157,995
ENGINE 4.0L twin-turbo DOHC 32-valve V-8/577 hp @ 6,250 rpm, 516 lb-ft @ 1,900 – 5,500 rpm
TRANSMISSION 7-speed twin clutch automatic
LAYOUT 2-door, 2-passenger, front-engine, RWD coupe
EPA MILEAGE N/A
L x W x H 181.0 x 78.5 x 50.7 in (est)
WHEELBASE 103.5 in
WEIGHT 3,428 lb (est)
0-60 MPH 3.5 sec
TOP SPEED 198 mph

2018 Porsche 911 GT3 Specifications

ON SALE Now
PRICE $144,650 (base)
ENGINE 4.0L DOHC 24-valve flat-six / 500 hp @ 8,250 rpm, 339 lb-ft @ 6,000 rpm
TRANSMISSION 7-speed dual-clutch automatic
LAYOUT 2-door, 2-passenger, rear-engine, RWD coupe
EPA MILEAGE N/A
L x W x H 179.6 x 72.9 x 50.0 in
WHEELBASE 96.7 in
WEIGHT 3,116 lb
0-60 MPH 3.8 seconds
TOP SPEED 198 mph

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