I've successfully upgraded my CLEVO W870CU notebook with the 7970M!
I would like to give kudos to the various people and topics that were of great help:
@t456 for the heatsink modification inspiration (and for replying to my messages), thank you! http://forum.notebookreview.com/threads/need-instructions-for-installing-alienware-dell-gpu-in-a-clevo.778988/#post-10050324
@yoshey791 for your random comment confirmed the 7970M works with Enduro disabled;