I just checked the
SoundStage! review (they always have some decent measurements as well) and it says they're rated to handle up to 300W. SPL calculator puts that at 105dB (reference level for movies) if you are sitting 6 feet away, with 300W/channel. If you're 9 feet away, you'll need 600W for reference level.
Since it's 8ohm nominal, and the impedance graph measured in the SoundStage! review shows it is fairly uniform, the speakers are an easy load. So I wouldn't say you need "expensive" amps that can double down or anything like that.