My experience with Magnepan's is just the opposite. My 1.7's sound much better being driven by the XA-25 vs the XA-100.8 monos. That said, I prefer the 100.8's with the Quad ESL-2905's.
Too much power?
I have a wonderful system with a great amplifier, and yet auditioned a more powerful version of the same amp. It indeed seemed to have more punch and drive, but at the expense of playing it a bit too loud. As my current system I rarely play over 70 db, since it’s perfect at low levels. I wonder other than bragging rights, what does more power get you? Since we aren’t here for PA style sound, is there a reasonable limit to how much you will benefit from higher power/ more expensive and? Especially since tire just using one watt most of the time?