Here's my current situation, I have a Yamaha 6295B 7.2 AVR with two Polk RTi A9's towers. At the moment, I'm bi-amping them and it sounds good. However, I'm looking to add a center speaker, a subwoofer and later on rear surrounds to the system. Will all these new speakers plugged in, I won't be able to bi-amp my front towers and it will suck up a lot of power from my AVR. What I would like is kind of another amplifier that would take the "out" front signal of my AVR and add some power to it before delivering it to my A9's. Is this possible? Is this a good solution? What products would be great for this? Thanks!