Newbie que on "recommended amplifier" rating

I currently have 4 Vienna Acoustics Bachs which, on Vienna's website, have an amplification recommendation of 30-200w. I am currently looking for an amp/pre to replace my very sad Onkyo receiver. I listen to 95%music and 5%home theater, but I really enjoy multichannel SACD and DVD-audio so I am looking for 5 channel amps like theta, simaudio and EAD. I like the pm 2000 for the money but it is rated at 400w into 8ohms and my Bach's are 6ohms so they would be seeing even more than that. In fact, even the theta and sim audio, which are 200w @8ohms would be above the recommended amplification into 6ohms. I want an amp that I can "grow into" (i.e. works with my next set of speakers) as well, not one tailored to Bach's specifically.
My long winded question is: Will these amps damage my speakers and, if not, where do these recommended amplifier ratings come from?