Does Gryphon Diablo 300 Benefit With A Costly Mains Power Cable?

To the op. Admittedly, I believe power cables are significant in the upgrades in sq they can make (of course, synergy is the ticket). However, based on what improvements you stated you are looking for (better clarity and separation, a more open and larger 3-dimensional soundstage and a brighter and more dynamic sound), I am thinking, your speaker / room / listening position should be an area for you to work on, as I am sure improvements can be made there. A "proper" power cable (if there is such a thing), should be as neutral as possible, no matter what the cost, allowing you to hear more of the component it is connected to. As a retired audio consultant with many years of experience listening to many systems / rooms, many suffer from mediocre room acoustics, and the speakers are not the right ones for the individual listener’s tastes / room. Keep in mind as well, the variety of the recordings we listen to (miking, mastering, all production artifacts, etc.), as this variation alone creates the never-ending upgrades many look for. I am not trying to be the devil’s advocate. Just what I have experienced listening to many higher end systems. The speakers, should meet your needs, wants and desires, in the room in which they are set up in, along with the acoustics of the space, from your listening position, are all paramount to achieve your best listening experience. Synergy will not happen otherwise, again, ime. My best, MrD.

Why buy a cord that you can return.  Ask some friends over for a Blind test. 
Let us know the results.

The Audioquest Dragon is the king of power cords for power amplifiers their power cords for lower power units are so so.

Hello @ryder , nice integrated.  In my experience, a good power cable will make a big improvement.

Having tried several Shunyata cables, I find them bright.  They sound dynamic and interssting at first, but fatigue then sets in.  My favorites are Kubala Sosna. Elation is great, Realization better, and Ovation out of this world.  Full, meaty, resolving but never too bright or fatiguing.  As many are upgrading to Realization or Ovation, both Elation and Realization can be found used or from GTT Audio taken in on trade.

On my Gryphon Diablo 333 integrated amp, the power cords made obvious differences. I cannot make specific recommendation based on your budget, but I believe an used AQ Dragon HC will be a good one, and maybe within your budget. But there are many fakes out there. If you can find an used or demo Stealth Dream PC that will be even better since I am not aware of fakes on the used market yet (I really like their Dream 20-20 power cable).