I own the Harbeth 30.2's and I can get them quite loud without any break up, provided the amp can output clean wattage. No fatigue at all, warm does not necessarily mean colored. I find B&W's a bit bright (only my opinion), but they are clean sounding. The Harbeth are a bit warm, but still clean sounding. A piano sounds like a piano, vocals sound like a live human voice. I do not listen to much classical, but I can crank Beethoven's 6th and 9th and it sounds wonderful.
I've own Adcom amps in the past and would say it's a good match for the Harbeth. I would suggest traveling to hear Harbeth and their other models. Their bookshelves with a sub sound amazing, the three ways also sound very good, but definitely sound different.