Mercedes-AMG GT S v Porsche 911 GT3 : Comparison Review

The Porsche 911 GT3 and its more hardcore brother, the GT3 RS, are not sports cars for the faint hearted. Bought by those seeking a proper track car that can double as an occasional daily driver, the GT3 remains as perhaps the best example of what a modern sports car can offer a true driving enthusiast.

Plenty of other manufacturers have tried over the years to steal the Stuttgart brand’s thunder - and pretty much all have failed. Now, though, the juggernaut that is Mercedes-Benz is going for the 911’s jugular with the Mercedes-AMG GT S.

After the much-loved Mercedes-Benz SLS AMG went out of production, its replacement was announced as the GT S, a car based on a modified SLS platform but now more focused on driving dynamics rather than being an outright Grand Tourer, which was the SLS’ real forte.

So, if you have about $300,000 to spend on a genuine sports car, you have a fair few choices. But, until the new Audi R8 arrives later this year or Aston Martin releases a Vantage replacement, the Porsche 911 GT3 and the Mercedes-AMG GT S remain the most obvious choices.

To find out which of the two is best, we drove out to Haunted Hills, a hill-climb circuit about one and a half hours South East of Melbourne.

Our two cars started life under $300,000. In the Porsche corner, our GT3 comes in at $293,600, plus $19,890 worth of options, while the Mercedes-AMG GT S is priced from a very similar $294,610 - but with $56,900 worth of options (full details at the bottom of review).

From the outside, it’s anyone’s guess as to which looks more expensive. While the SLS had the allure of the gullwing doors majestically sweeping open with a spaceship de-pressurisation sound for added affect, the GT S is a more conventional car.

It still possesses the same characteristics of a long bonnet, though, and a deep, low cabin that helps bring its ideal weight distribution to fruition. Besides, let's be honest, it looks like a very expensive Mercedes-Benz. However, considering the brand starts its range these days below $40,000 with the A-Class, that might not necessarily mean anything, particularly when it’s pitted against a Porsche.

The Porsche 911 GT3 looks like a 911 with a bigger wing. Sure, it has heaps of other external modifications, but to the average person, it’s just a 911 with the sort of wing that little boys used to hold on to when they drove their model cars around. And for that reason, we love it.

Power and engine

The engines that power these two cars couldn’t be more different. Having all but given up on naturally aspirated engines, the folks at Mercedes-AMG have utilised a 4.0-litre twin-turbocharged V8 with 375kW of power and 650Nm of torque for the GT S, while the purists at Porsche have continued to keep the GT3 naturally-aspirated at heart, but its 3.8-litre six-cylinder heart still delivers a remarkable 350kW of power and 440Nm of torque.

The bug-eyed German utilises a seven-speed dual-clutch Porsche Doppelkupplungsgetriebe (PDK) transmission, which although may seem like a relatively new concept for some manufacturers, has been in Porsche’s racing parts bin for well over three decades.

As such, it’s easily the more distinguished shifting system when compared to Mercedes-AMG’s rear transaxle-mounted seven-speed dual-clutch transmission.

Both being rear-wheel drive also provides opportunities for some fun, with the Merc more likely to impress at a drift meet than the rear-engined GT3. The Merc will hit 0-100km/h in 3.8 seconds, while the GT3 manages that in 3.5 seconds.

On the track

There’s no chance that an average driver or even a wannabe race driver, like the one here, could ever extract the true performance from either of these cars. They both offer the levels of speed and agility that require a professional racing driver’s finesse to fully understand and then exploit.

So from an average driver’s perspective, the Mercedes is the easier of the two to drive fast. It feels more like a video game, in that its power-steering system feels overly assisted and the sensation of speed is generally masked by the car’s extreme composure.

The additional 210Nm of torque from the V8 helps the AMG exploit its speed on the straights - there aren’t many at Haunted Hills - but point it straight and flatten the accelerator and the GT S flies with an exhaust note that will leave even the biggest Porsche fan in awe.

The brakes (a $17,500 carbon ceramic option in this case) felt as though they could last an entire Le Mans endurance race and, having done over 25 fast laps, my very unfit body showed no signs of complaint.

That, we felt, was the GT S’s main point of concern for those seeking a dual-purpose track car. It’s too easy to drive. The learning curve of making the GT S perform at a reasonable level is far lower than that of the 911 GT3.

While you will find yourself far more comfortable initially in the GT S than the GT3, each passing lap finds you getting faster in the GT3, yet you’ll begin to plateau in the Mercedes-AMG and begin to rely on later braking points rather than carrying more speed into a corner at the right angle.

The Porsche 911 GT3 has a roughly 200kg weight advantage (1420kg) over the Mercedes-AMG, so while it lacks a bit of torque, it makes up for it in weight. The PDK gearbox is also a step ahead, performing like a rapid-fire German machine gun in comparison to the slightly jerky Mercedes-AMG system, which, while still excellent, is no PDK.

A lap in a Porsche 911 GT3 at full speed is extremely exhausting. We mean that in the absolute best way possible. The 911 makes you sweat to go fast and consequently makes driving it one of the most exhilarating experiences one can have in a road car.

Got a line wrong? Here’s some understeer. Accelerated 30cm before you were meant to out of a corner? How about a spin? The track got wet? Hope you’ve got a signed will. Everything you do, has to be perfect. Mistakes are not tolerated.

After plenty of warm up laps, we did five hot laps with the same driver in each car, trying to set the fastest time. While the Porsche felt genuinely faster from behind the wheel, in the end the GT S beat the GT3 by about half a second, with both cars using the exact same tyres. If there had been more straights, the gap would’ve been even wider.

The GT S has beaten the GT3 around numerous other race tracks around the world, too, so its performance is not in question. But if the question is, which is more enjoyable to drive on a track, the Porsche is the solid winner.

On the road

The Mercedes-AMG GT S is an easier car to live with as a daily driver. It’s easier to get in and out of and, at the very least, ticks the basic boxes such as rear parking sensors and a reversing camera.

The GT3 is a nightmare to park, with its huge wing, limited rear visibility and no parking sensors, even as an option. It’s a cruel German joke, that if you’re going to buy a GT3, you should learn how to park it. We get that, but for it to be used as a daily, you don’t want to be sweating each time you’re getting in a tight car park that someone’s left a trolley in, or if you’re reversing out on to a road. Having a camera is crucial when you really can’t see behind you.

The GT3 is annoyingly road compliant, in that 'how is this possible' way. Considering how good it is as a track car, it doesn’t make sense how comfortable it can be on the road. In saying that, the GT S is still better as a daily driver. It’s still even more car-like and less likely to misbehave on a poor road.

The GT3 likes to be driven hard, all the time. As such, it’s not that fun to drive around in heavy traffic. You can tell that it hates it; it can jerk at times from constant low speed acceleration, and if there’s even a small hint of rain, it becomes somewhat daunting.

On the other hand, the GT S in comfort mode becomes like a plush C-Class with a semi-mute V8 burble. You can have a cup of tea in it and no one would look twice. In the GT3, though, there’s no way you wouldn’t burn yourself.

Cabin and interior

Porsche is a company of evolution. This has been the case not only in the way its cars look, but also how they perform. This also applies to the interior, which is old-school compared to the Merc.

There’s an over-abundance of buttons, each performing a single function. That’s the Porsche way and, while it may work, it doesn’t look or feel as upmarket as what the folks at Mercedes-AMG have managed with the GT S.

The Porsche seats, with the harness, make going fast more fun. Given there’s no movement in the seat, you feel more comfortable pushing harder - and you need to feel that in the GT3, because it’s not for the faint hearted.

In contrast, the GT S seats are a little wider and more forgiving for us larger folks, while the infotainment system and the whole centre dash cluster feels a generation ahead. As does the stereo.


Regardless of which we think is the better car, what’s obvious is that Mercedes-AMG has created a true alternative to the Porsche 911. If you’ve been a long-time Porsche 911 owner and want something different, the options have grown by one.

Nonetheless, as a track car, the 911 GT3 is unrivalled, even by its faster GT S competitor. The Porsche remains the more engaging car to drive and brings a surreal sense of enjoyment to track sessions by demanding 110 per cent of a driver’s mental and physical capacity.

While the initial learning curve with the Porsche on a track is much higher, hitting what feels like at least 90 percent of its ability appears to be within reach with more and more practice. The Mercedes-AMG however, seems to be far easier to drive at first, but you quickly reach a point where it no longer feels comfortable to push harder, whereby the GT3 is always putting the onus back on the driver rather than itself. They are both so very different.

If road compliance and every day practicality was the key point here, the Mercedes-AMG would easily be the winner - but these cars are for those that truly love the art of driving and wish to enjoy every minute of freedom behind the wheel. With that in mind, it’s the Porsche 911 GT3 that is the choice for us between the two Germans.

Click the Photos tab for more images by Tom Fraser
Videography by Christian Barbeitos and Mitchell Oke

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