230W is quite possibly in the range you are able to get out of the Pioneer give or take a few watts, at least that is what I can get out of my 3808, so I am looking for double that, 500W, for an outboard amp.
You could look for a cheap mono amp to drive the center or even use that one you linked to in bridged mode.
I doubt it, my pio is rated around 110w/channel for 20hz-20khz. This is a vendor info and can't find the real output that the AVR is capable for an indefinite time range. This could be a peak rating.
