I'm in the process of upgrading to a rack system, and my next purchase is a power conditioner. I had always planned on getting a Furman PL-8, but I was looking through my MF catalog and there's an RP-8 series in there too. The PL-8 lists for $159 and sells for $119, and the RP-8D lists for $189 and sells for $99. Kind of weird huh? Getting back to my original question does anybody know the difference between the RP-8 series and the PL-8? Also, do I really need to know what the AC line voltage is?