Quality PC: plug into wall socket or conditioner??

Well, since you have the aftermarket power cord and the power line conditioner, you could try it both ways and decide for yourself.

This hobby is so subjective, with synergy and personal tastes amounting for so many differences of opinions, that the only way to know what works best for you is to do the experimenting for yourself.

Agree this issue is a 'You have to try it for yourself, and decide which sounds best' type.

For example, I bought a few of the better Pangea powercords. So I have a few pangea AC9 and then the more expensive AC9SE. I stuck an AC9SE from wall to Furman power conditioner just to 'break it in' and was shocked it really made EVERYTHING sound better. WOW. Never thought that could happen.

Anyway I then went and tried the better cords in all the places I had other IEC cords.
And some places the new Pangea AC9SE was the best. In others, suprisingly, the AC9 was better sounding. A few the AC14SE sounded best.
For my PS Audio P600 the AC9 was a lot better than the AC9SE.But for my Bryston Preamp the AC9SE was the better one. With the AC9SE on the Furman, Which cord to my amp? I left the AC9 as not any difference I could hear with AC9SE to amp.

So you have to experiment. Really no possible 'rule' is going to cut it in the real world for which cord should go where. Every system is different.
And do not dispair if you cannot hear any difference.
For now, it does not matter. When time passes you may nnotice a difference as you stuff gets better.(even breaking in can change it all.)

And really if you can't hear any difference do not worry about it. Some stuff there is not a whole lot of difference.

I just plugged my amp and preamp into the wall, after having both in power conditioner, and found the wall was surprisingly better. Same result with my integrated amp. Told two audiophile friends who did the same and much preferred the wall. I still have my digital and analog sources plugged into the conditioner.

Awesome!
It depends on a lot of things. I live at the end of the grid and the power is really spotty. Otherwise, amps into walls is often a good idea. I think front end stuff benefits most from conditioners....but the listen and match up is the way to do it. Aftermarket PC's are the bomb and if the one you have isn't making a big difference, try another because eventually it will.
All that said, I ended up with a big hospital style Topaz isolation transformer in my basement on a dedicated line....it's out of the way anyway!
Rule of thmb is best pc to your condition. I think I gave myself a hernia wresting with an Elrod Statement once!