I for one think Boxster sales will be hurt if Porsche does not keep the performance increasing. There are clearly roadsters in the price range of the Boxster (Corvette, Z4, etc) that will trump it big time in horspower etc. and do quite well in the handling dept too.
If I were Porsche, I would not sacrifice the roadster just because they have a product strategy with the Cayman.
"Hopefully Porsche will wake up, stop trying to separate the Cayman S from the Boxster S, and update the Boxster S with the Cayman goodies to keep up with the roadster competition"