SPY PICS: Porsche Cayman GT4 RS

Spy photos of a sinister new mid-engined sports car likely to be called the Porsche 718 Cayman GT4 RS have been snapped at the punishingly fast 21km road course that is the Nurburgring… where else?

Porsche has never produced an RS version of its brilliant mid-engined coupe before, but an even more focussed Cayman variant than the epic GT4 has been a badly kept secret for a while.

And judging by the motorsport-inspired aero additions to this stealthy, blackops-look Cayman prototype snapped here, Porsche looks set to take the GT4 recipe to the next level, even if it treads on the toes of the brand's flagship 911 coupe.

At $206,600 plus on-road costs (putting the most expensive Cayman within $30,000 of the cheapest 911), the manual-only Porsche Cayman GT4 is propelled by a 309kW/420Nm 4.0-litre naturally-aspirated six-cylinder boxer engine that revs to an impressive 7800rpm, and features an equally-focussed interior and road-hugging body work.

But the new mystery machine spied here wears even more assertive new front apron and an even bigger rear wing. Take a close look and you’ll also see Naca air ducts on the bonnet not unlike those on the Porsche 911 GT2 RS, plus improved cooling for the mid-mounted engine via air inlets that replace the rear side windows.

An extended front spoiler and a considerably larger (and presumably more adjustable) rear wing than the Cayman GT4’s are also in evidence, as are new alloy wheels with single centre-locking nuts usually found on race cars, instead of the regular five-stud set-up.

What’s not clear is what engine is sitting behind the test driver – and what sort of lap time he nailed around the Nurburgring.

Porsche's 4.0-litre 9A2 flat six would deliver tremendous torque if turbocharging was employed, but this would reduce throttle response, lower peak engine speed and push power even further into 911 territory (the base model makes 285kW/450Nm).

Instead, expect to see several lightweight internal components increase the 9A2 engine’s redline even further, along with other weight-saving measures.

At the Porsche Cayman GT4 launch in mid-2019, Porsche’s boxer engine development manager Markus Baumann told carsales: “We could of course get more power. When we take the technologies from the GT3, like the titanium con-rods, or the dry sump … when you apply those technologies to this 9A2 engine it can create much more horsepower than 420hp [309kW].

“We have those technologies already developed and we could easily bring them together [in 9A2],” he added.

Porsche Cayman GT4 video review

“You have two possibilities. Either decrease the friction, the ventilation losses in the crankcase — that’s what a dry sump does — or go to higher engine speeds to create more power.”

So is peak power of 335kW/450hp possible?

“I would say everything is possible, it’s just a matter of effort,” said Baumann.

With serious upgrades to the powertrain and chassis making it Zuffenhausen's most ferocious mid-engined model, a potential price tag of close to $300,000 for the Porsche Cayman GT4 RS is also possible.