Another big factor is your home vs. the audio store room acoustics. Are you using the array as a center channel or as a stand in for the whole front stage? If the latter is true your room acoustics may have an even larger effect because you can't really rearrange the LCR very much. The array specs say it is 91 db efficient which should allow you quite a bit of headroom even for smaller amps, but...the power specs are for two channels driven only and you will likely get less than 100wpc if using more channels. You don't indicate if you are using a subwoofer but if you are not a decent sub could help out with headroom issues because it reduces the amount of power your receiver has to use to produce lower frequencies which allows more to be available for the array.