You will here very little differance. The upgrade will give you 1)features 2) connection options. The onkyo's have a sound signature
think as an accent. They are not changeing this as this is what people want.
Pioneer, onkyo, yamaha, Rotel, B&K some times they do a change up. but then you here big time about it. eg. Pioneer SC-05/07 are
not the same sounding...
If you don't like the sound signature from the receiver it is time to move on.