I'd spend $500 more and retain my "upgradeitis" peace of mind.
Not sure, but I think this is a mistake on C-3 page... So called "fission" PSU-s are TOTL regenerative PSU units available (only?) in and for HE units. If you give a look at C-3's PSU module you can see it is very very similar to Phoenix's PSU module, and I'm pretty sure Phoenix does not have regenerative PSU (although it has really good PSU on its own).
Of course, nothing (beside price increase?) stops you from ordering C-3HE, RE-7HE or NFB-7HE... and getting the ultimate PSU A-GD offers for their gears. Just look for the "HE" suffix.









