Power Cable ~ $300 - Which to get? Nordost, Audioquest, Furutech, Shunyata, Zavfino?

Synergistic Research Master Coupler. Hands down. One and done. Not that I would ever recommend buying anything like this without comparing several contenders, preferably in your own system. 

But look. SR has been making this same power cord for over 20 years. In all that time one would think it would have been superseded or faded to obscurity. But no. Instead they are still out there selling at higher prices than originally and commanding good prices even in the used market. Like it or not, it is the gold standard of power cords. Nothing endures like that for no reason.

I notice you mention OCC. Sorry, but who cares? Someone who hasn't been around long enough to see that for the marketing BS it is. None of that malarkey matters in the least. All that matters is how it sounds. Get a Master Coupler and find out.

If you decide on Nordost, the Blue Heaven has similar construction as their upper end.

I use Nordost from the wall to speakers. If you put in the time, you can find decent used prices. 

what is getting plugged into the 'bar'?

everything?

sources only?

amps only?

checking out wires is the 'due diligence' of this past time. it gets very tedius but this area will pay off with effort and paitience. personnally I'd look into the used PC arena first. you'll get more value and performance for your money.

my reasons for asking what is the application revolves around the 'kinds' of PCs.some are aimed squarely at deadening the noise, others at elevating other aspects of the bandwidth. not all PCs are the same and with EXP you'll find this out pretty quickly.

if I liked AQ and already had some in my rig, I'd probably look towards them initially. possibly even exchanging one already in use to the duty of supply, from where it is already in use perhaps.

lastly as the main supply PC keep in mind too, it will add its sonics to everything downstream of it.

Good luck.