^ Agreed on both counts with pretty much everything you said. Seems we hear a few things similarly. The 007 and 009 even from the BH, KGSSHV or T2 weren't enough to pull me away from the modded 800 w/ my rig. But the Omega is something special, probably the best midrange I've ever heard in a headphone. If it had a bit more bass punch and impact when called for, it would be pretty damned close to perfect along w/ a well driven HE90.
A couple things:
1-I think it was covered but somewhat lost in the nuance of the discussion by some, but high output Z is not a requirement for proper synergy w/ the 800. I know my modded Super 7 puts out around 4 ohms and I've heard a few decent SS implementations w/ zero output-z and objectively beautiful measurements do quite well (the O2 not being one of them). It's definitely a case by case, circuit by circuit determination IME. I would not go dropping 43 ohms after every amp simply because of whatever the HDVD800 does.
2-On the mod, try to be as precise around the ring area as possible, a shift of less than 1mm in position or size can have a significant impact and make the ringing/peak even worse. As for the link to the rabid dawg mod, that's about 3 prototypes old now and anyone can feel free to give it a go. Material selection is key though, and you have to really pay attention to what you are using, they are not all the same. Hope to have a pre-fab kit available in a few months that will offer the end user a few subtle flavors to select for their preferred rig and tastes.