Well, the answers on these question is pretty short-no power increase for Cayman S. Price for Boxster S(with 3.4l Cayman S engine) will go up at least 5000Euro IMO.
Both base Boxster and Cayman will get more powerfull version of 2.7l(variocam plus) engine.
Same engines in Boxster and Cayman in all version-lower production cost for Porsche-more money out of costumers pocket-more cash flow for Porsche.
That how is work in Porsche clinic these days...