The 2021 Porsche 718 Boxster GTS 4.0 is a naturally-aspirated version of the existing 718 Boxster. Essentially an update for the current 718 Cayman GTS, the GTS 4.0 ditches the turbocharged, 2.5-liter flat-four engine in favor of a 4.0-liter flat-six mill.

The engine is shared with the range-topping 2020 718 Boxster, but detuned in order to slot the GTS 4.0 lower in the lineup. Unveiled alongside an identical version of the 718 Cayman, the 2021 718 Boxster GTS 4.0 hits the road with 394 horsepower and various suspension components borrowed from the 911 GT3.

The GTS 4.0 also marks the return of the naturally aspirated engine in the 718 Boxster lineup (beyond the Spyder model of course), but it will probably be offered only for a limited time. Let's find out more about it in the review below.

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Exterior

Just like its coupe sibling, the 718 Boxster GTS 4.0 looks a lot like the regular GTS. The latter also looks very similar to the regular 718 Boxster, so it's a bit difficult to set the GTS 4.0 apart from its simpler siblings. If you like sleeper sports cars, than the GTS 4.0 is the perfect choice.

However, looks close enough and you will notice a handful of extra features. For starters, there's some black detailing that's not offered on the regular Boxster. The front spoiler lip and the front air intakes are finished in black, while the headlamps feature darkened lenses and black backgrounds.

Around back, the taillights also feature darker lenses, while the lower bumper section, which incorporates the diffuser and the tailpipes, is finished in black. It's also here where you'll notice the most important feature that sets the GTS 4.0 apart from the other Boxster models. It's the twin-exhaust layout borrowed from the range-topping Boxster Spyder. You can't get this setup on any other Boxster models.

Finally, the GTS 4.0 runs on a unique set of 20-inch light-alloy wheels painted in Satin Black. The rims are wrapped in high-performance summer tires as standard. The "GTS 4.0" decals on the lower doors will also remind you that this isn't a regular Boxster.

Of course, the GTS 4.0 features all the other defining traits of the current-generation Boxster, like the taillights stripe with "Porsche" lettering, the revised rear fender intakes, the four-point LED headlamps, the skinnier daytime running lights, and the wide and thin front bumper vent.

Interior

Porsche interiors are rather flat across the lineup, with only a handful of features setting them apart. This applies to the Boxster too. Upgrades compared to the regular model are mild and mostly about materials that give the cabin a more race-inspired look. The steering wheel, for instance, is wrapped in Alcantara in this model, a feature usually found in Porsche's race-spec vehicles. It also includes a stripe at the 12 o'clock position.

The regular seats in the standard Boxster were replaced with the Sport Seats Plus package, which comes with sportier units with enhanced lateral support. The seats are also wrapped in Alcantara for even better grip during spirited driving. You'll find more Alcantara on the gear lever and the armrests on the door panels. The A-pillars and the headliner is also covered in this soft material.

The entire interior is black as standard. This is supposed to enhanced sportiness as professional race cars are mostly black on the inside, but it tends to become boring. So if you want to avoid this, Porsche offers an optional GTS Interior Package that adds decorative stitching and details in different colors.

The rev counter, seat belts, the stitching on the seats, the embroidered "GTS" emblems on the headrests, and the "Porsche" lettering on the floor mats are available in either Carmine Red or Chalk. The standard trim elements are in carbon-fiber, which is cool, but you can opt for other materials like aluminum or simple black trim.

In the tech department, the 718 Boxster GTS 4.0 comes standard with the Porsche Communication Management (PCM) system. It includes a high-resolution seven-inch touchscreen, the Sport Chrono package, and the latest Track Precision App. The latter is based on a design used in Porsche race cars and shows performance-related data on the display, while also recording it for later analysis. The online navigation module with real-time traffic information, voice control and Porsche Connect are optional, as are the Bose Surround Sound System and Burmester High-End Surround Sound System.

My only complaint here is that the display is smaller than the industry standard, but we're stuck with the seven-inch screen until Porsche redesigns the 718 lineup.

Drivetrain

The engine in the GTS 4.0 is the most important bit about this mid-engined roadster. When Porsche revised the 718 back in 2016, it replaced the flat-six engines with turbocharged, flat-four units. It offered a 2.0-liter in the base model and a 2.5-liter in the S version. All hopes that the 718 will still carry a naturally aspirated engine went to the dumpster when the GTS was unveiled, in 2017, with a more powerful version of the 2.5-liter turbo in the Boxster S.

Needless to say, some Porsche enthusiasts weren't very happy with this move, despite the many advantages of a turbocharged drivetrain. Sure, the 718 Boxster Spyder remained naturally aspirated thanks to a 4.0-liter flat-six, but that's a limited-edition model that's highly expensive. As a result, the German firm decided to offer the 4.0-liter in a more affordable car. Yes, this is where the "4.0" badge comes from. The GTS 4.0 is a Boxster Spyder with a detuned engine.

This mill shares displacement and layout with the engine in the 911 GT3, but it is actually a different design.

Since Porsche doesn’t want to dilute the GT4, it detuned the engine to 394 horsepower, while torque remained unchanged at 309 pound-feet. That's only 20 horses below the GT4, which isn't bad at all.

Compared to the regular GTS, fitted with the 2.5-liter turbo, the GTS 4.0 boasts an extra 33 horsepower. But before you start celebrating, you should know that the naturally aspirated engine pushes out less torque. Specifically, the 2.5-liter turbo cranks out 317 pound-feet, eight more than the 4.0-liter flat six. Compared to the Boxster S, the GTS 4.0 benefits from an additional 49 horses and identical torque.

When it comes to performance, the GTS 4.0 is quite fast, although it's not the quickest Boxster you can buy. The sprint to 60 mph takes 4.3 seconds, a tenth-second slower than the slightly more powerful Boxster Spyder. Compared to the turbocharged GTS, the GTS 4.0 hits the benchmark a tenth-second quicker. But only when compared to the manual version. The PDK-equipped GTS reaches 60 mph in 4.1 seconds, two tenths quicker. It's also slower than the PDK-fitted variant of the Cayman S, which boasts similar torque.

But there's some good news in the fact that the GTS 4.0 is slower than less powerful variants of the Boxster.

Moving over to top speed, the GTS 4.0 hits the maximum velocity at 182 mph. That's seven mph slower than the Boxster Spyder, rated at 189 mph. On the other hand, it's two mph faster than the turbocharged GTS. It's also five mph faster than the Boxster S and 11 mph faster than the entry-level Boxster.

While it may seem that the engine is borrowed from a race car, the 4.0-liter flat-six is actually very friendly when it comes to daily driving. It feature adaptive cylinder control that switches off one of the two cylinder banks at low engine loads and it's fitted with direct fuel injection with piezo injectors and a variable intake system. All three devices help improve fuel economy, although Porsche has yet to release specific figures.

The list of additional features over the regular Boxster includes a sports exhaust system and a standard Porsche Active Suspension Management system. The latter lowers the ride height by 20 millimeters (0.8 inches). It also features a Porsche Torque Vectoring (PTV) system with mechanical limited-slip rear differential, which delivers a good balance between dynamic handling and everyday comfort. Stopping power comes from cross-drilled discs that measure 13.8 inches in the front and 13 inches in the rear. For increased performance you can go with the optional Porsche Ceramic Composite Brake system for increased performance.

Prices

Pricing information for the U.S. version is not yet available, but it's safe to assume that the GTS 4.0 will sit between the GTS and the Boxster Spyder in the lineup. The GTS is no longer available in the U.S., but the Boxster Spyder is still on sale and it starts from $96,300.

Competition

Alfa Romeo 4C Spider

If you live in the U.S., the 4C Spider is the only authentic alternative to the 718 Boxster GTS 4.0. It has similar dimensions, a similar weight, and the engine mounted behind the seats. Recently discontinued in coupe trim, the 4C remains available as a convertible, but production won’t extend beyond 2020. Already seven years old as of this writing, the 4C boasts a cool Italian design, and in many ways, it looks better than the Boxster Spyder. The interior, on the other hand, suffers in certain areas, especially on the technology front. Under the hood, the 4C Spider comes with a tiny, 1.7-liter four-cylinder engine. The turbo unit cranks out 237 horsepower and 258 pound-feet of torque, which places it way below the GTS 4.0. But even though it’s not as powerful as the German roadster, it’s not significantly slower, needing 4.5 seconds to hit 60 mph from a standing start. The good news is that it’s notably more affordable than the Boxster GTS 4.0, retailing from $67,150.

Read our full review of the Alfa Romeo 4C Spider

Conclusion

With sales of the 718 range having dropped compared to previous years, it's not surprising that Porsche is bringing back the 4.0-liter flat-six. But even though it might create new hype for the nameplate and increase sales, it will only be temporary. There's no way Porsche will keep the naturally aspirated engine beyond the current generation. Not only emission requirements won't allow it, but Porsche has made it clear that turbocharging and electrification are the future. So enjoy it while it lasts, because the GTS 4.0 won't be around for long.