The only naturally aspirated Porsches produced today are the GT3 models. A new Cayman GT4 is likely on the way and if so that likely means it would have to borrow either the GT3 or GT3 RS engine as the old flat-6 from the Carrera S is no longer produced.
Then again, the 991 GT3 and GT3 RS engines share many parts with the 991 Carrera S on which the 981 GT4 motor is based. The Cayman GT4 RS obviously will not be allowed to step on the toes of the GT3 or GT3 RS so expect power to be reigned in somehow.
Rumors are output of 425 horsepower at the moment. Will the GT4 RS be manual only? Will it come at all? There is a lot to speculate on here.
Let's hope this is a real leak and it's coming.