Porsche 911 GT3 S/C review: Open-top cars don't come any better

Are you pining for a Porsche 911 GT3 without a roof? Now there’s a concept, one that’s not yet been filled in the 911 lineup — until now, at least. It sounds almost juxtapositional, the idea of a hardcore and uncompromising sports car but without a roof, which reduces body stiffness considerably and would likely make the car weigh more. But Porsche engineers have delivered a spectacular machine that was never supposed to exist.

Revealed back in April, the GT3 S/C was essentially born from a impulse of Porsche‘s development engineers, who decided that combining the hardcore underpinnings of the GT3 coupé with the bodyshell of a convertible 911 was a great idea. Ensuring that the challenging open-top project did not betray the fundamental character of a thrilling, lightweight racer, extreme weight-saving measures had to be implemented across the board.

Weight has been a key target for engineers, as convertible variants typically weigh a lot more than equivalent coupes due to the extra strengthening needed to keep rigidity in lieu of a roof. As such, the bonnet, wings and doors are all made from lightweight carbon fibre. Same for the anti-roll bars.

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As you’d expect for a sports car of such a high calibre, carbon-ceramic brakes are standard equipment. Compared to a conventional braking system, they save more than 20kg of crucial mass, while also easily putting up with repeated track punishment. Filling the arches are gorgeous forged-magnesium wheels: 20 inches at the front and 21 inches to the rear. In total, these special wheels further reduce the car’s mass by a significant 9kg. 

Other obsessive weight loss details include a battery that weighs 4kg lighter than a standard unit and even the supporting and load-bearing structural elements of the fabric soft top are made from magnesium.

The result of this intense engineering effort is a kerb weight of exactly 1,497kg, which is incredible. To put that into perspective, the new GT3 S/C is a full 30kg lighter than the celebrated 991-generation 911 Speedster, which is a car still considered the benchmark for a lightweight, open-top performance machine.

Inside the GT3 S/C’s cabin, the quest for more weight reduction is obvious. Porsche has used the same lightweight carpets and stripped-back door panels that were featured in the exclusive 911 S/T, while even the interior door handles have been swapped out for carbon fibre replacements to shave off a few more precious grams.

Buyers are given a choice of seating as you can stick with the standard four-way electrically adjustable sports seats, or opt for a set of carbon-fibre buckets. Our test car featured the latter, which held us perfectly in place during hard cornering.

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Ahead of the driver, the focal point of the digital instrument cluster in the GT3 S/C is the rev counter, which is what you’d expect in any serious Porsche product. By engaging the dedicated ‘Track-Screen’ mode, the driver can instantly reduce the digital display to cleverly show only essential driving data. The digital dial can also be customised so that the magical 9000rpm redline in the GT3 S/C is positioned dead centre at the 12 o’clock mark.

You might be wondering why that redline so important and that’s because this naturally aspirated 4.0-litre flat-six boxer engine really feels at home when it is pushed right to its limits. The sound it produces is simply intoxicating, while in Sport mode, it sings a glorious song, accompanied by thumping, rev-matched downshifts.

The performance figures are just as impressive as the soundtrack: 375kW of power and 450Nm of torque. This incredible power propels the open-top sports car from 0-100km/h in just 3.9 seconds. By the time you hit that speed, you haven’t even hit third gear through the wonderfully precise six-speed manual gearbox. 

Keep the throttle pinned and 200km/h arrives in less than 12 seconds, with the car eventually topping out at 313km/h. To keep the 911 firmly planted to the tarmac, the rear spoiler automatically deploys at 120km/h to increase downforce.

Dynamically, as you’d expect for a GT3 variant, the S/C is an masterpiece. It features a highly advanced double-wishbone front suspension system, which is a first for a convertible 911. Engineers originally assumed that the standard GT3’s track-focused rear suspension would need an overhaul to compensate for the additional weight of the folding roof sitting over the rear wheels.

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However, after testing, they discovered that tweaking the suspension by a mere one per cent was all that was needed to give the S/C excellent stability in all driving situations. The steering is also excellent, responding sensitively from the dead-centre position without ever feeling overly nervous or twitchy.

Should the clouds start to turn grey, the fabric soft top can be electrically operated in just 12 seconds and at speeds of up to 48km/h. Once the roof is fully lowered, an electric wind deflector can be deployed in just two seconds and at speeds up to 120km/h, to allow for a more.

At a starting price of $588,500 plus on-road costs, the GT3 S/C is an undeniably expensive play toy. It is slightly disappointing, then, that on a car where almost everything feels uniquely premium, the button panel for the hazard lights is made from cheap-looking and simple plastic. Our only complaint is admittedly quite a small one.

Overall, the Porsche 911 GT3 S/C is a thrilling sports car that blends technical excellent with genuine soul. By combining the emotional, high-revving nature of the naturally aspirated flat six engine with the open-top driving experience, it’s a unique machine that effortlessly puts a permanent grin on its driver’s face. It’s obviously not what you’d call cheap, and you can still spend plenty more on options, but the 911 GT3 S/C is simply the best open-top sports car currently available.

Porsche 911 GT3 S/C specifications: