PCBuild for NOS1a

[music33]

I have been reading as much as I can about how to improve the sound quality for the NOS1a.  A lot of the threads were before the NOS1a.  Here are some of the things I've read about -
PCIe filter card, Peter Pang audio grade USB card, upgrade USB cable (YFS), linear power supply, BNC connectors for interconnect and 500+ tweaks to the OS done by Peter. 

For the NOS1a how which of those things above are still relevant and would make the biggest impact. 
Has anyone tried the Isotek ATX 275 linear power supply?

Many thanks for any responses.