I am not a power cord guy
. So I will comment on the USB bridge. The one in our showroom is powered by Audiophilleo USB to S/PDIF bridge. I tested it without it and the bridge definitely makes an improvement. We have the Berkeley unit on order but unfortunately there is a delay in production so it will be a few more weeks. For now, the Audiophilleo can be had for $500. I would certainly put more money toward this part than the power cord
.
Oh, I do have something to add on the power front.
I have one of the older PS Audio programmable power regenerators. I was pleasantly surprised to see it make no difference with Berkeley and Audiophilleo. So power sensitivity is quite low in these products if it exists at all. BTW, on my old Mark Levinson DAC, there is was an improvement with the PS Audio.