To be clear, I got all that, and thanks. But I meant "your worse case scenario" as others have already commented that the 5308 is fine, one even said it would do better than the Outlaw 5000 (if I understood him right). So my intent was to give you feedback based on "worse scenario", example: that you may want to crank things up once in a while, so instead of volume -10, may be -5, or even 0? Or you may listen to 5 Ch stereo, without cutting back from volume -10? Or you may occasionally, for certain music, run the LSi9 full range, and they do have very good bass response for their size. I don't do that but apparently some people enjoy that mode.
So again, what I am talking about are:
"maximum seating distance, full range or with sub and crossover setting (okay you did say 80 Hz, but always, or would do full range sometimes?, maximum SPL you listen to, would you run 5 ch stereo mode, do you listen to music that has low dynamic range at loud level? "
If you are not interested in "worse case scenario" requirement, then I concur with others, you don't need to pair your very capable AVR with a power amp, but I definitely would encourage you to put two fans on top, to protect your very nice AVR.