It won't fit unless you get new mounting brackets for the calipers. The mounting points are not the same. You'll probably have to have some custom fabbed.
They will with quite a bit of work, don't know off the top of my head... but the mounting points are different for sure... but why? just adding big red's up front will really upset the boxster's brake balance.. which could in 986S form use a touch more rear bias as it is........