The 7500 would work fine that that mix of speakers.

As a general rule, the sorts of things you mention (separation, clarity, headroom) are common goals - and common rewards - when going from a receiver's amp section to a separate amp. As Bugbitten points out, you may not end up using any more power than your receiver presently has, but the power supply and amp design are both going to be significantly more robust. Looking back at my transition from receivers to separates, I would expect you to hear just the sorts of things you mention. I've actually got some comments in my 7500 review (see my sig for the link) about the subtle improvements it offered over my other separate amps - you're likely to experience more of the same from a receiver-to-amps upgrade. And since the AVR 235 has pre-amp outputs , you'll have no problem adding a separate amp .