Power Cords, Should they all be from the

My system consists of four dedicated 20 amp ac outlets, PSAudio P300, Black Mamba on CD player, Sidewinders feeding Bel Canto Evo digital amp and P300. Should all the power cords be from the same manufacturer in one's system? Anyone with a similar set-up? Any recommendations such as upgrading the pc feeding the P300?
I'm totally biased here, since I sell the Powersnakes, but my experience is that with the high-end power cords, PLCs usually make things worse instead of better, and vice versa. I used to own the Power Plant 300 and found the 'Snakes to offer better improvement, but of course, YMMV. As for keeping all the power cords in the same family, that I would definitely agree with. But then I also feel that all the interconnects in one's systems should be from the same family too. I'm sure opinions differ on this, but that's my experience at least.
I am comming from a different direction. A variety of power cords can make components sound different. Find the combination that sounds the best to you. All expensive pc's don't always make the best music. Mikeg, your set-up of pc's sounds good based upon my experience, however you never known what will happen by mix-and-match.
Until I got into the Powersnakes and FIM power cords, I prefered to mix and match. With the Powersnakes, you'll vary the models throughout the system, KC frontend and Cobra/Viper on amps. The FIM is the first brand that their Gold power cord can (and should) be used throughout the system regardless of the component. The FIM Gold is a very special product.
I don't agree with the dealers comments on the Power Plants. As many discussions here on Audiogon have discussed, the best power treatment for your system will depend on the quality of the AC power delivered in your neighborhood, the RFI situation in your neighborhood and your equipments reaction to that environment. Additionally some digital equipment even in the multi kilobuck range throw huge amounts of junk on the power lines. This isn't a subjectivist observation, it can been seen with good test equipment. Other than the standard recommendations on grounding and dedicated AC lines you are on your own. Even with dedicated AC lines and dedicated grounding my AC power is full of garbage since it is supplied by the first underground neighborhood distribution system dating from the from the 1920's yet due to the configuration of the hills I'm relatively RFI clean. The Power Plants make far more difference in my system than any expensive powercord. But then I have unique power problems.
I concur with Pls1, in my system, the P300 made a much bigger improvement than power cords alone. My "two cents" are that each component has its own "character" and AC current requirements. I found, with some experimentation, that logic applies (mostly)in that the heavier gauge AC cords work better with high current Amps, tube gear, etc. So I guess to answer, IMO its not necessary to use cable from the same manufacturer any more than you would buy all the same components in your system from the same company. And these cables ARE "components", aren't they? For what its worth, the two biggest improvements in my system recently, were the addition of (2)PS Audio "Lab Cables". One for my Classe CA301, and one for my P300. Unbeleivable improvements for both. Live long & prosper.