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

Thanks @audphile1 useful to know. I’ll look at the Kimber PK10 Ascent power cord. Low price is surely useful and appealing to everyone. It’s just that most cheap is considered as not good, and it’s refreshing to know that some may deliver great results at a fraction of the price. 

@ryder 

Well they aren’t cheap. PK10 Ascent is around $500 for 1m. To me that’s reasonably priced. Kimber makes a higher tier Palladian cables that have been highly praised in reviews but I haven’t tried them. They offer 60 day return policy if you buy direct from Kimber. Zero risk. Kimber are solid cables and their customer service is top notch. It’s not about low cost, but best sound. 
Compare with Shunyata and several other cables to see what works. May be even try the Palladian PK10. 

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.