I was able to use VT-d no problem on C1 chips, there is an issue according to intel but I think there might have been a bios patch around it. I tested passing through multiple types of cards and it was fine.SR0KX is a C2 stepping which has VT-d enabled. SR0H8 is a C1 stepping. It depends on whether you need VT-d or not.
EDIT: See this post Intel Xeon E5-2670 Deal and Price Tracking