I tend to agree with the above -- the reason that the Golden Ear 3d Array XL sounded "great in the showroom" was almost certainly a function of how much smaller most audio shops are so that you are significantly closer to the speakers than in your living room and what the rest of the gear in the demo was consisted of. The additional headroom of the Yamaha receiver probably helped give better dynamics to essentially all the peaks that are feed to the speakers but if their source was something much better than what you are accustomed to or they had some amazing subwoofers either of those things could make it impossible to compare to what your living room is ever going to sound like..

By switching over to the 976 and adding even the Outlaw Model 5000 you get an amp that is rated as delivering 100w into EACH of the the five channels as opposed to the Onkyo receiver which is only rated to deliver that with two channels loaded... http://outlawaudio.com/products/5000.html

I would have a hard time saying whether or not the result would be "dramatically better" without knowing all the details BUT I've never seen a situation where more power was not a good thing for even the most modest home theater. Toss in the potential for 7.2 and future of 4K and this should be a slam dunk...