The power question comes from me reading someplace that to reproduce the sound level of a real piano takes 200 Watts.
That's nonsense. And no, you should not get the most power you can afford, but the best power. I believe Bob Carver was one of the people hyping the idea that anything less than a few hundred watts would clip, or some nonsense like that, something no reputable study has reproduced.
Good 90 Watts beats mediocre 300W any day of the week in home reproduction. If you are trying to fill an auditorium you might feel very different.