dkidknow:
I seem to have heard differences in cabling, including power cords, and as I said, I have not heard conspicuous differences with dedicated lines. (Of course, lines not an easy change to meaningfully A/B).
So I hunch you'll hear more from the outlet than to the outlet. FWIW, I think you'd hear more with the same dollars in things besides cabling -- for example, a well considered 2100$ upgrade to speakers.
(One exception might be if if your kit is on a heavily loaded circuit: I suspect one could hear the draw of a refrigerator cycling.)
All things considered, though: my advice is to do the AC. My reason for this has to do with psychology unrelated to sound: now is the time to do it, since it will be an expensive hairball later, and if you stay in the hobby, you'll regret not doing it. From the wall improvements can always be done the next time you are feeling spendy, but not the AC, at least for a sensible price.
So my vote is to do the AC, and sleep well, secure in the knowledge that you are doing everything right. :)