But just which engine will it use?
Every iteration of the Cayman and Boxster that Porsche has offered has packed a six-cylinder engine – right up until the current one, which ditched the atmospheric six in favor of a turbo four. But that's about to change, and not just with the GT4.
Automobile claims to have it on good authority that the German automaker will slot another six-cylinder model into the 718 lineup between the four-pot GTS and the forthcoming Cayman GT4 (and Boxster Spyder). And it could emerge as the purist's choice. We just don't know yet which engine that will be.
As it is, the Cayman GT4 and Boxster Spyder are poised to borrow its 4.0-liter atmospheric flat-six from the outgoing 911 GT3. So far Porsche has only released the track-tuned GT4 Clubsport, which employs the previous version's 3.8-liter flat-six, rated at 419 horsepower and 313 lb-ft of torque.
Zuffenhausen could re-task that (or another naturally aspirated boxer six) for the as-yet-unnamed new variant, or crib a different, turbocharged flat-six from the 911 lineup. But one way or another, it'll likely spread out the power gap between the various iterations of the 718 Boxster and Cayman.
The 2.0-liter turbocharged flat-four in the base and T models kicks out 296 horsepower, the 2.5-liter version in the S models produces 345 hp, and the GTS tunes the same for 361 hp. With the GT4/Spyder expected to pack a good 400 hp, the new model would likely fall somewhere around 380 hp, which would probably be about the same as the new 992 Carrera. (So far we've only seen the 444-horse Carrera S.)
Its approach and nomenclature represent additional question marks. Porsche could position it as a softer version of the hardcore GT4/Spyder, or simply as another step along the ladder.