I was originally going to go with the Hedmans, but the way my impulse buying has been going, I didn't want to wait the 2 months lead time for back-order. So, I went with the Hooker Competition ceramic-coated 6921s. Mine is also a 351C-2V, but I stuffed an AOD in behind it, which is very close to FMX dimensions.
What I did notice is that there were no fitment issues with the power steering system whatsoever; brackets, pump, hoses, or otherwise. So, I guess I'm having a hard time seeing where the power steering pump would be an issue. Now, the PS gearbox - that might be an issue, and I can honestly say there's no problem with that either (with the Hookers). So, I'm thinking if you can get by the C6 issue, you should be fine with the 6921s.
Make sure you order a set of collector adapters, since Hooker's pretty tightwad about such things (the Hedmans included everything). I got the HOK-11040HKR (Summit) (the black collectors pieces) to mate up to my Pypes 2.5" stainless exhaust, and had to bend out the lead-pipes to match up the headers inward angle to the straightness of the exhaust. See below:
Here's a straight-forward shot of how the headers fit in there beside the tranny (again, it's an AOD, not a C-6):
Hope that helps!