They can get plenty loud, and they can take plenty of watts. In fact the more power the better, they really deserve a high-power amp; that helps fill out the bass end of things.

My amp puts out 115 watts per channel at 8 ohms -- but note the MMGs are 4 ohm speakers, so double that: about 230 watts per channel. That's just about enough juice, in my opinion.

You'll need to make sure you get an amp that can drive 4 ohm speakers. And beware power ratings for cheaper-end receivers, they probably aren't accurate.