difference between P300/P500 and UPC/UO

PS website states that their passive conditioner can lower noise by 40db while their power plants can lower noise by 70db. I'm curious to hear from anyone who has done a comparison between the two. Any difference in sound?
any one?
I can simply tell you that my p500s are dead quiet on my system which is saying something given my amp and preamp are solidstate Yamaha MX1000U + CX1000U from 1979 (not even a change of caps has been done on these units) with 3 sets of the large, vintage McIntosh XR-7 loudspeakers from the same period. I would think that more modern equipment should be even quieter. I favor + play a lot of analog but also employ SACD, CD, audio mixer, equalizers. Dead quiet with whatever I run (or record as I have both Tascam CD and cassette tape recorder). The only exception is when I dub my live music over recorded via my mixer, which in this case I know it is the mixer introducing the background noise. I highly recommend the P500 or P1000 depending on your needs.