best power conditioners under 4k

Right. But not for the reasons you think. You're still getting noise from your appliances, and everything else for that matter. All that happened was you improved that one little thing. You can do the same for every inch of wire both before and after the conditioner. Which you could have done instead of the conditioner. And let's see that thing cost $1800 that would get you, ... uh huh.... right. You could have skipped the conditioner and had even better sound with unfiltering. Way better. And that's to say nothing of the panel and lines. All because it doesn't work the way you think. Oh well....

I use Shunyata conditioners in my main system and Furutech in my other system.  Systems are dead quiet with no lack of dynamics. 

Right. But not for the reasons you think. You're still getting noise from your appliances, and everything else for that matter. All that happened was you improved that one little thing.

Improved a major issue to the noise floor. I'm living in an old rowhome in an old neighborhood with shared lines, shared transformer and ungrounded houses.

Of course, appliances are adding noise; they're wired to the panel on both legs. Tweaks could be used here, but right now I'm satisfied with the improvement.

I loved my BPT and Audience, but liked it better when I removed them months later...

Unsure about 'best' option, but the Decware ZLC works well, is about 1K shipped and returnable.  Spending copious quantities does not ensure results.