Power Conditioners

Sean, as is usual with his expertise, is right on the money.
Powerwedges and the early Brisson stuff were the first plc I experimented with and they made the system noticeably quieter. I did not find, that they reduced dynamics. I've also used Equi/Techs( balanced power= less noise) and the PS Audio stuff, to run US voltage equipment here in 230VAC country with no detrimental effects at all. With the Bybee powerconditioners I tried, I did not really notice much difference, neither with the Tice stuff. But I found the TAD, an early Bybee attempt, which is without current protective devices, subtly increased the dynamics on the preamp,(Spectral DMA 30) I used it with. I've never tried the really expensive Accuphase and Burmester gear, but I am very happy with the PS Audio 300 and 600, which also helped to make my system somehow subtly quieter and its rendering more "relaxed" and naturally musical.

Try the Monster Cable one. At $179 it is much cheaper than many of the others and it works well in my system. (I cannot say that I have directly A/B'd it against the competition, but the improvement is noticeable and I like the price!) They also have a slightly less expensive one with fewer outlets. (System: Thiel 1.5 speakers, Golden Tube SE-40 monoblocks, Modulus 3A preamp.)

You may want to add the Sound Application CF-X to your list, I own both and the CF-X beats the Hydra hands down.

I have also used those Blue Circle BC86 Noisehounds Power Pillows. They are a parallel filter. They so not have outlets. They work wonders if used with a low cost conditioner. Even with a high end conditioner, I notice some difference, mostly in the blackness of the background.