It's been a long time since we saw a prototype of the new Porsche 718 Boxster Spyder being put through its paces. This time, the roadster has been caught undergoing some cold winter weather testing, which probably won't be the car's natural habitat.

The recent reveal of the track-only Porsche Cayman 718 GT4 Clubsport renewed hope that the Boxster Spyder and the road-going 718 Cayman GT4 will be powered by a flat-six engine. However, Porsche's head of GT Customer Motorsports, Matthias Scholz, has confirmed the road going GT4 won't use the old 3.8-liter engine from the GT4 Clubsport. Andreas Preuninger, head of GT road cars at Porsche Motorsport, also confirmed the Cayman won't be getting turbo power.

That means the 718 Cayman GT4 and Boxster Spyder will likely be powered by the 4.0-liter flat-six used in the 911 GT3, just as previous rumors suggested.

Obviously, Porsche isn't going to let the lesser 718 model match the hardcore GT3's power, so the 4.0-liter flat-six will likely be detuned from 500 hp down to around 425-430 hp. A six-speed manual will come as standard, while the seven-speed PDK dual-clutch gearbox will be optional. To save weight, the 718 Boxster's electric folding hardtop will also be replaced with a manually removable "tent top," and features such as air conditioning and radio will also be removed.

Given the lack of official teaser images released by Porsche, it seems unlikely that we'll see the Cayman GT4 and Boxster Spyder debut at Detroit next week. Instead, they will probably make their public debut at the Geneva Motor Show in March.