Take a look at this:
Yamaha RX-A1030, RX-A2030 and RX-A3030 Aventage Receivers Preview | Audioholics
And:
Comparison Chart:RX-A3030,RX-A2030,RX-A1030 - AVENTAGE - Audio & Visual - Products - Yamaha United States
I have not seen a review in which the actual power is measured for these (though I have not looked much for it, so there might be one to be found with a search). Judging from the rated power, the difference between the amplifiers in the different models is small (it takes a doubling of power to get just a 3dB difference in volume, which is easily noticeable, but not dramatic).
They all three have preamp outputs, so you can add separate amplification if needed. That, by the way, favors the low end, to give you more money to spend on the separate amplification.
Also, when new features come out that you feel you need, you will be replacing the receiver, but you don't need to replace any separate amplifiers you may have. So my advice tends to be to tell people that they ought to buy the least expensive receiver that has all the features they need, and put the rest of their money into things that make a more significant difference in sound, like better speakers (including subwoofers).
With your selected speakers, there is a dip down to about 4 ohms; see:
Aperion Audio Verus Grand Loudspeaker System Review | Audioholics
With that in mind, you could go with an even lower end Yamaha (I recommend staying in the Aventage line from Yamaha) with preamp outputs and go with a power amp from the start. But how high up you should go in the line is very much a function of the features you require. And looking at the Yamaha web site, I like the feature upgrade that one gets going with the RX-A1030 instead of a lower model, but what features you want may not be the same as what I want.
From a sound quality standpoint, there will be little or no difference between them, provided that the amplification of them is enough for your specific speakers (or if you use a separate power amp). I used to use a receiver that retailed for about $600 with speakers that retail for more than $6000, and it sounded great (as it should). I replaced the receiver with one that retailed for about $1700 because I wanted more (and newer) features, and unless I engage a feature that affects the sound, it sounds the same as before. Keep that in mind when selecting your receiver; in my opinion, most people put too much of their money in electronics, and not enough in speakers, if actual sound quality is the goal. And receivers are not as good for long term investments as speakers, because companies tend to come out with new features that one wants, even though one may not have thought that there would ever be anything lacking that one would ever need in the future, when one selected one's receiver. But they are good at coming out with new improved features, so you will likely want to replace your receiver in a few years no matter what you buy. But with speakers, if you buy really good ones, you may never need to replace them.
