I recently purchased Bose AM 5 speakers, which I am very displeased with. I did not do my research and I expected to be able to expand on the system - instead I would need to buy a whole new AM system. Now I am interested in the Polk RM6750 system because it is Polk and it's in my price range. Does anyone have an opinion about them? I have a Yamaha RX-650 AV, and I understand the Yamahas are generally considered crisp AVs - is the RM6750 a good match?

Also, I am seeing that most of these Home Theater speaker systems have powered subwoofers and that it's not recommended you connect them directly to the subwoofer connection on the AV (I am new to this). What's the downside to this vs. a standard subwoofer?

Any and all help much appreciated.