I passively Bi amp my Maggie 3.6's with a pair of David Berning ZH270 power amps. The result is much better sound from my Maggies then using one amp. In fact I won't get 3.7's because with there series crossover you can't bi amp. I also when I was upgrating one of my bernings I thru a vtl ST80 in to replace one berning and it sounded just as good. One nice things about the Berning amps is they have volume controls so I can adjust bass/mid levels versus the treble level.
Alan
Alan