Advice on best upgrade path for a Mac Mini setup

Hi all,

My beloved PWT transport was shipped out for service last week, so in the mean time I decided to experiment with the Mac Mini which usually resides in my 2nd system. It was no surprise that it doesn't even come close to the PWT, but it sounds OK, and now i'm curious as of what I can achieve with it without spending another $2K.

It's a stock Mac Mini about 2 years old with an SSD drive.
I'm using it to stream TIDAL Hi-Fi.
I have it hooked up to a Schiit Wyrd USB re-generator via a Pangea silver USB 2 cable, which in turn is feeding my DSD via a WireWorld Starlight 7 USB 2 cable.
My thinking was that the Mac-to-Schiit path will be less critical in terms of cables, as it gets regenerated anyway, but I'm open to listen and learn...
That "Wyrd Schiit" re-generator did make quite a noticeable positive impact when I hooked it up in my 2nd system.

My question is - what will be the best bang-for-the-buck upgrades? 

I guess the switching power supply is a weak link so I looked at Mojo Audio stuff and those prices seem unreasonable - they want more for their power supply than what I paid for my PWT (including its superb power supply).
Any other recommended power supply upgrade kits?
I'm good with DIY and can probably do the upgrade myself.

Perhaps go with much better cables? Better isolation? Better re-generator?
What did you guys try that proved to really do the "magic" for similar setups?
Perhaps it is a 'losing battle' and it will never sound nearly as good as my PWT without spending $2K in upgrades?

Thanks for your advice!

Ami