The original Porsche Cayman GT4 was an outstanding car but it felt like Porsche hampered it to protect the 911. With the new 718 Cayman GT4, it feels like Porsche is making a greater effort to finally unleash the Cayman platform and let the engineers make it as good as possible. It is now powered by a 4.0-liter naturally-aspirated flat-six producing 414 horsepower and 309 lb-ft of torque mated to an enthusiast-pleasing (albeit slower) six-speed manual transmission.

This sounds like a recipe for utter driving pleasure but Porsche has already admitted it can extract even more performance from the Cayman. A Cayman GT4 RS has been rumored for several years now but our spy photographers just capture a prototype which could be the real deal.

What we see here could be the long-rumored 718 Cayman GT4 RS. Judging by the NACA ducts for brake cooling, side window louvers, and massive rear wing, this will be the closest thing to a Cayman racer for the street Porsche will build. The rear wing especially, though it may not be the production unit, shows this car is being built to tear up race tracks.

Under the hood, Porsche has already said the GT3's titanium connecting rods could be easily adapted to fit the GT4's flat-six engine, meaning the company would not have to resort to turbocharging to extract more power. 450 to 500 horsepower could easily be in the cards, though we suspect Porsche will still want to distance the GT4 RS from the more powerful 911 GT3 as much as possible.

As for the transmission, we suspect a track-focused Porsche RS model would likely ditch the manual transmission in favor of a faster PDK, which would drastically improve the GT4's 4.4-second 0-60 mph time and track performance (although it would sacrifice on fun). The production GT4 RS (if that ends up being the final name) isn't expected to make an official debut until summer or fall 2020 as a 2021 model.