I'm about to buy a used Stewart World 2.1. I just noticed that my Furman RP-8 says it can handle no more that 1800 watts. Does this mean that I can't plug the Stewart, which can put out 2100 watts, into it? Or if I do that I wouldn't be able to use the full power of the Stewart? Or are these the wrong numbers to be looking at? $500 is a good price for a used 2.1, right? Thanks!