The Parasound Halo A51, putting out 250 watts per channel, has plenty of gain for the speakers. I would vote for the 3.6s if you are ultimately headed in that direction. As for amplifier upgrades later, you might consider Parasound Halo JC1s or perhaps tube amplification. The JC1s will be cleaner, sweeter and more musical and rhythmic than the A51. You could use the A51 for the bass if you choose to biamp the 3.6s, and in the meantime if you have the other channels of the A51 available, you could use four channels of it to biamp the speakers. Disclaimer, I am a Parasound Halo dealer; I hope this post helps you. Good listening!
