Thanks Casey, on this board its pretty easy to tell if the M2 card is seated, you can actually see the bottom of the card inserted into the slot which is kind of nice. The Asus board is a little harder to tell but I do believe its installed properly, no mention of it in IORegistry Explorer at all, went looking under rocks earlier for it.
I got past the grey screen, I think the bios got corrupted, reflashed it and now I can see where it hangs. I think it is a security setting that gets flipped on when the thunderbolt controller is enabled in the bios. Here's a shot of what gets changed and where it hangs.
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