Porsche is again testing what appears to be a hardcore 'RS' version of its latest 718 Cayman GT4, with the latest mule spotted in minimal camouflage at the Nürburgring.

As we previously saw, the testing prototype sports notable bodywork additions. At the front, there are versions of the Naca bonnet air ducts similar to those on the 911 GT2 RS, while the rear quarter windows have been replaced by slatted cooling vents. A new addition are the blanking plates at the front, which suggest the hardcore Cayman will gain similar wing-mounted air outlets to its 911 GT3 RS sibling.

A large, bespoke rear wing – significantly larger than that of the standard GT4 - appears to be mounted higher and to use a new mounting design. Also changed over the standard GT4 are the wheels, which forego the traditional five-lug pattern in favour of a motorsport-inspired centre-lock mechanism that hints at the car's track potential.

The man in charge of the 718 and 911, Frank-Steffen Walliser, told Autocar at the Frankfurt motor show last year that he would “definitely” like to see a faster and even more focused RS version of the new 718 Cayman GT4 but that the decision hinges on prioritising development resources within Porsche.

“Everybody’s asking for the RS,” Walliser told Autocar. “Can I imagine a GT4 RS? Sure I can. That’s not to say we will make a decision on it yet, as it is a challenge. Would I like such a car? Yes, definitely! Would I like more horses? Yes. But we need to put the resources where the market is; it would be a lot more expensive than the normal one.”

Porsche has never made a GT4 RS, previously suggesting such a model would be too close in price and performance to 911 GT models. But the new 4.0-litre flat six found in the latest GT4 forms part of an all-new engine family, and it's expected that Porsche will spin off further variants of that unit to justify the investment.

It's understood that the brand is looking to reintroduce the flat six to more mainstream Cayman and Boxster variants as part of a facelift. Although Walliser would only confirm that Porsche has “started the thinking process” on this, he acknowledged that the US market has been less welcoming of the current four-cylinder models than hoped. “American customers aren’t asking for four cylinders, they're asking for four litres,” he said.