No problem! I think I wasn't rude or anything?
I just requested to post in that thread, because that's where everyone is posting their issues and there's also a lot to read.
As far as I know, there're barely any differences.
The only differences are the wave gen parts, some "C" models have them (Can be converted to "D"), others doesn't.
Of course, all "D" models do have them. And that's very much it the differences we know at hardware level.
I've tested all firmware versions, none fixed the sync in lower voltage modes.
Such a shame.