Power regeneration - good idea? PS audio?

I have the entry-level PS Audio P3 feeding my Class-D Rogue amp and my sources. I think it lowers noise floor and improves articulation. I listen to mostly acoustic and classical, so I find it worthwhile. Maybe not the most “bang for the buck” $1500 I ever spent, but I never considered returning it.

I talked to Torus and they say that noise <20kHZ is not filtered out. Regardless what the measurement says, I think the acid test is whether it sounds as good during the day as during the night.

Is there that much of a difference between 117 V and 121 V coming through your system?

That's about what my variation is throughout the day

I think it would be interesting to measure the distortion level at my home. Can anyone recommend a meter for this?

A good multimeter like a Fluke 789, but I bet there are cheaper ones.