I'd skimp on the Dura Ace cranks, you're paying more for the name OP
This high up in the crank hierarchy, you're paying for brand & scarcity & looks basically. And don't go into X is stiffer than Y because they're all as stiff as origin 8 cranks for all you should care.
The same goes for chainrings, you're just blowing your money away with a zen...
Some guys, I'm not going to name who can't get enough of it. "Educate yourself, fool."