Dmloring: Your amp is indeed powerful enough, provided your room is of modest dimensions. The demo I heard was with a receiver that output around 30 watts/channel.
As for the "fullness" of the minuet's sound, that, IMO, is one of the most surprising aspect of the Minuet. You expect a mini-monitor to have a big soundstage, and the Minuet does, but it also gives off the impression of having a lot of bass output. I doubt it actually extends very deep, probably not much below 60Hz, but I was surprised at how much it sounded like it did indeed go deeper.
I agree it's a leap of faith to buy speakers unheard with no return policy (which is why I had to drop Silverline Audio's Adagio - since discontinued - from my potential upgrade list). That said, most used pairs sold here on the 'gon seem to sell for around $350 or so. So keep that in mind as a way out if you're not happy. Lower priced gear tends to sell fairly quickly if it's in good shape and a current production model.