Your understanding is correct; as a general rule your speakers would call for a minimum of 80 watts per channel, for "most audiophiles, most of the time." That's my rule of thumb, anyhow.
That said, if your need for loudness is modest or your room is small, you can get away with 6dB less, or 20 watts, and if both, maybe even as little as 5 watts. On the other hand, if you want large-scale symphonic extravaganzas, you might need 300 watts, and for live rock-concert levels maybe 1200 watts. It's not an exact science ... :^)
(Modest loudness means chamber music, jazz quartets, and the like - or for many people, quiet enough to not annoy the neighboring apartment/flat. A small room means something like 10 square meters/100 square feet or less.)
So yes, the BeePre2 with the upgrade for balanced outs would appropriate.