I agree with Mudshark and Highbar, the Beta series is built for use with typical home theater receivers, that is, they are meant to be easy for almost any amplifier to drive.
I'd also like to point out that what the dealer said; "The thing that hurts speakers is when you have too little power not too much", is a bit wrong.
The thing that hurts speakers (or the voice coils at least) is too much power, clipping can damage speakers because an amplifier will produce more wattage when it's clipping than when it isn't clipping.
If a speaker is rated for 300 Watts, 50 Watts will not hurt it - even if the amp is severely clipping, conversely, even an unclipped 1,500 Watts will damage the speaker.