I didn't know that the M30's were easy to drive. I'm only experienced with the compact 7's - great speakers - I hear they like mid-higher powered solid state, although others have used tubes. The Portal Panache is a wonderful integrated, sometimes found used for 700-900 dollars, supposed to have a very good headphone out (uses same amplification as speakers, not an opamp), 100wpc designed by Nelson Pass. Very neutral in presentation. The Leben CS300 gets great reviews, though I don't know if it's enough power for the Harbeths.