I got off the phone with a client yesterday. He went through the entire process I specify. He reworked his grounding, panels, subpanels, branch wires. He got rid of as much aluminum as he could. He did it all accept for install an isolation transformer. After he finished the work he tried an Altaira. He heard nothing, so he returned it.
I have had other clients do the same, rework their electrical. When done, they get rid of filters they plug into the wall. Not all of them. Some. A few filter in particular go, and a few stay.
Reworking your electrical can be as expensive as a component. And you can't remove it and sell it for 40% of what you spent on it. But I believe it is the foundation of all audio based music. It is as necessary as a speaker, amp and source. If you are missing any one of the 4, you don't have a functional audio reproduction system. You can live without everything else. You don't need a stand, room, footers, ground box, filter. You don't need any of it.
If I was spending $$$ to upgrade my audio performance, I would put a ground box as very low on the list of to do. I would put optimizing your electrical up there with speaker and room. It’s a very audible change the investment. I would put an isolation transformer in well before a ground box. They cost close to the same or less when you start adding in all the ground cables.