I have over twenty pairs of caliper adapters to adapt Boxster calipers to 914 -911 front struts or rear trailing arms. I have not yet sorted out which adapters fit what except for ones that were marked for Boxster to 911 or 914 front or rear. I have the suspension and calipers to mock up about any combination.
Asking $75 a pair for any set.
More details to follow. If you have combination you need adapt let me know and I will mock it up.