I can't imagine the difference between the v661 and the 805 being very large.  I sure there is a difference but probably nothing compared to the 200watt setup. 

 Too bad I live in New England because otherwise I would offer bringing my AVR over to your place to hook it up and let you put it through the paces.  My AVR is not in the same category of the equipment you are looking it but it may be an interesting comparison between the 2 still, since I am not experiencing the kind of things you are having a problem with.

 Either way let us know how you make out Dan.  Even though your setup isn't totally satisfying you, it is still a kick ass setup..

Rockarruda

I will let you know once I get the AVR-3805 hooked up.

I'm thinking for efficeint speakers that differences may be sublte but in terms of an 84 DB speaker there may be some audible differences.

Also noticed that sound and vision mag did some test benches on both the Yamaha RX-V661 and the AVR-3805

You will notice that the RX-V661 only produced 56 wpc on the 5 channel driven test

http://www.soundandvisionmag.com/receivers/2276/test-bench-yamaha-rx-v661-av-receiver.html

Whereas the AVR-3805 produced 107wpc on the 5 channel driven test

http://www.soundandvisionmag.com/assets/download/DenonAVR-3805lab.pdf

 That's almost double so I'm thinking that will help bring more life to the 5B's.  I'll let you know how it turns out.