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In order to stuff the 911 GT3’s flat-six into the back of its mid-engine Cayman, Porsche leveraged some truly creative engineering. One of the biggest problems Porsche’s engineers faced was getting air to the engine, letting it breathe. Porsche’s solution, which in turn allowed the Cayman GT4 RS as a whole to breathe to life, is unorthodox.
The Cayman’s rear quarter windows have been replaced by intakes. Those intakes feed the engine’s airbox which sits just behind the driver’s head. It works, allowing the wonderful 4.0-liter flat-six to fill its lungs. It also turns the cabin into a theater of induction noise. This is easily one of the loudest new cars money can buy, and not in a trash-can-sized exhaust kind of way: The Cayman’s cabin creates a soundscape comparable like the legendary McLaren F1, more glorious induction whomp at full throttle than exhaust note. Magic.
That 4.0-liter six still revs to 9000 rpm. It has 10 fewer horsepower than the GT3, but only because the routing of the exhaust creates back pressure which saps power (it’s not some intentional detuning to maintain the 911’s position on the Porsche hierarchy). That engine pairs to a new seven-speed PDK gearbox, which is the only available transmission. Porsche had to Frankenstein the drivetrain together to make it all work, creating a sort of ‘greatest hits’ of recent GT cars. Engine from the GT3, flywheel from the GT4 Clubsport Race Car, limited-slip differential from the 991.2 GT3 manual, and shared ratios with the 991.2 911 GT3 RS. Don’t be sad there isn’t a manual gearbox here, this PDK has the shortest gearing of any RS Porsche, meaning you won’t even hit 100 mph in third gear. It’s perfect.
Improvements to the Cayman formula abound. The GT4 RS’s suspension uses ball joints. The car is also equipped with larger brakes, revised cooling, and heavy use of carbon in the body. Part of the 991 Carrera 4S’s body is even integrated into the GT4 RS’s construction. That makes the RS stiffer and allows for the addition of a front axle lift, needed so you don’t grind the car’s nose off at your local Starbucks. Altogether, the GT4 RS weighs 3227 pounds, 49 pounds less than a PDK GT4. Impressive, especially since the larger (16-inch) front and (15-inch) rear brakes, wing, revised fascias, and body ducts are heavier than the parts they replace.
The optional Weissach pack takes the lightweighting to further extremes; the hood is left as unpainted carbon, as are the mirrors, side air intakes, and rear wing; the tailpipes are constructed from titanium and designed to look like the ones on the legendary 935. Right now, nearly everybody who has placed a deposit on the GT4 RS has opted for the $13,520 package. And if you opt for the Weissach Pack, you’re then able to option the 20-inch magnesium wheels. These wheels are expensive but provide a healthy reduction of unsprung mass. But can you really put a price on weight savings? In this case, yes, and the cost to cut 21 pounds is another $15,640. The tire is a Michelin Pilot Sport Cup 2, 245/35/20 up front and 295/30/20 out back. And if that isn’t enough grip, you can option the ludicrously sticky Cup 2R.
And while you might mistake a Cayman GT4 for a regular Cayman, there is no mistaking the RS. The body is transformed, a sea of NACA ducts, carbon fiber, and aero-optimizing goodies. There are revised wheel wells that reduce body lift, larger air intakes, brake cooling ducts on the hood, air inlets where the rear windows should be, fender vents, and a swan’s neck rear spoiler. The interior is familiar Cayman, with sport bucket seats like you’d find in a GT4 or 911 GT3, fabric door pulls like other RS models, the GT3’s PDK shift lever, and random bits of carbon so you know that you’re in something trying to whittle off every extra pound. This is the most serious, quick, and wildest mid-engine Porsche since the 918 Spyder.
It’s a riot.
You notice the sound from the go. The airbox is essentially in the cabin, inducting air around your head, ballistically loud. While we’ve loved the operation of Porsche’s double-clutch gearboxes, we’ve often lamented that the ratios were too tall to enjoy in the real world. This new PDK’s gears are so short that the transmission rips off shifts like a motorcycle. The engine flies to redline, like it has the world’s lightest flywheel, and that next gear is grabbed instantaneously. It’s a barely controlled mania that reaches a vibrant crescendo before every shift.
That’s paired with one of the friendliest chassis out there. The mid-engine layout has always been the inherently better design in Porsche’s sports car family. But due to tradition and other reasons, the Cayman has been held back from outperforming its rear-engined brother (at least, that’s what the tinfoil hat types said). Finally, we lay that conspiracy theory to rest. The GT4 RS feels eminently adjustable, a wonderfully neutral thing. It defaults to understeer at constant throttle during cornering, but the RS can be coaxed into line or out of shape by a lift or dab of the throttle. And thanks to the car’s steering, which feels direct and chattery, the platform communicates exactly what it needs to make you look like a hero.
Yet, this is the first Cayman that needs you to think about throttle application. With 80 more hp than the next-most powerful variant, it requires a little more thought and care when tromping on the gas. Be ready with your inputs, though, and it’ll never bite. The GT4 RS’s brakes also clamp down like monsters. The new, larger rotors and six-piston front and four-piston rear calipers are solid, always inspiring confidence, with no fade after multiple laps.
In three sessions on the newly repaved Streets of Willow following Porsche factory driver Patrick Long and pro driver and instructor Mark Hotchkis, the GT4 RS behaved like a willing and shouty dance partner. While it had no way of keeping up with the 911 Turbo S that the pros were driving in the straights, it was able to carry more speed in the tighter sections and pile on the brakes later than the larger 911. The experience left me feeling like a hero while hassling the pros (who were certainly driving far below their limits). The GT4 RS also sounded so much better than the Turbo S, a high-revving hornet’s nest posing as a sports car.
The sad thing is, the GT4 RS is sort of a final love letter to this Cayman and its mid-engine platform. While it’s not going out of production immediately, this Cayman’s replacement is coming, expected to be fully electric and to debut in the middle of this decade. If there was ever a time to put the wildest naturally aspirated engine the company makes into its best platform, it’s now.
And what a car it is, a masterclass in theater, precision, and plain fun. It’s the rare car that can be called great after just a minute behind the wheel. And it’s the sort of car the Cayman should’ve been all along. The base price for the GT4 RS is $143,050. You’ll never find one for that price. But if you do, mortgage everything and buy it. These will never be that cheap again.
Travis is an editor at Road & Track. He was previously the Editor-in-Chief of Jalopnik.com and is a little too fond of the Mazda Miata.
