Unsound, good point. If he's driving the Thiels to high levels in an 18x18 room, he's got more problems than amp power; he'll be working on hearing loss. 4 Ohm nominal impedance, 90dB sensitivity. He'll be fine. I have used integrateds (i.e. Pathos Classic One MkIII, Eastern Electric M520, Dussun V8i) at moderate listening levels with less efficient speakers and they all have worked perfectly.
Now, if he wants to blow the walls out... that's a different story. Most audiophiles I know do play their gear louder than I do, so take that into consideration.
True, he can get more power with separates, but likely more cost and potentially more mismatches in gear. It's a trade off. He may want to stick with a one brand solution then.
