I've posted this elsewhere but think that it really deserves its own post.
On the subject of engines, here's a thing:
All current 981 and 991 cars use the Gen2 DFI as a base. According to press reports, the GT3 RS will use a 4.0-litre version of the new [Gen3?] engine as will the 3.0-litre [?] and 3.4-litre [?] turbocharged flat-6 engines in the revised 991.2 Carrera and Carrera S due later this year. The new 2.0-litre [?] flat-4 engine is also rumoured to be a 4-cylinder version of this engine, which would make sense from the production standpoint.
This means that the 981-series cars as well as the 991 GT3 and Turbo will still be using the Gen2 engine for the time being. We have to assume that the GT3 and Turbo will be updated to Gen3 spec at some stage and we must also assume that a flat-6 will still be available in the revised 981.2 Boxster and Cayman, but will it be the Gen3 engine or a run-out version of the Gen2? I presume that the Gen3 will just be a development of the Gen2 and assume that they're dimensionally similar but a GT4 wouldn't use a N/A 3.8-litre GT3 engine and the Carrera engines would be too small a capacity in N/A form for the Boxsters and Caymans, so there would have to be 3.4 and 3.8-litre N/A versions of the base engine for the S, GTS and GT4 cars.
Preuninger has said that GT4 production time will be limited and that the GT cars will be normally aspirated for at least a couple of years and we're anticipating 2-years delivery of GT4s but beyond that, who knows? I'm sure that the GT4 will be successful and will become an established part of the Cayman line-up but it's impossible to say what engine it'll have. Hopefully it'll track it's GT3 sibling and have a N/A flat-6.
I think that it's accepted that the next generation of Caymans [MY2018?] are going to be turbocharged but will a flat-6 turbo be included?
Just my thoughts of course.
Jeff