Webbs, welcome. The standard shouldn't be "perceived quality", but rather the reality of actual audible performance; perceptions(especially on some audio discussion boards)sometimes bear little resemblance to the reality of a situation. Engineers have learned how to design receivers which have audibly flat frequency response together with inaudibly low noise and distortion. This is available to us these days at quite modest cost and in the vast majority of cases a receiver is the sensible cost-effective option. Using two or three boxes instead of one doesn't carry any magic with it.
Any amplifier can drive any speaker, including one rated at 4 ohms, and doesn't know what the impedance is. It has to supply the necessary voltage and current, as determined by Ohm's Law, for a certain amount of power required for a given loudness level. When it does that the impedance of the speaker doesn't matter, so the question is how loud and how long a certain amp/speaker combination can operate.
It's highly likely that the Onkyo 805(or even the 705)which you're considering will fully meet your needs. Possibly the best buy at this time would be the factory refurb offered by
Accessories4less , an authorized dealer, for about $700 with free shipping.
