I once repaired receivers. Onkyo's where bullet proof. They are usually overbuilt and underrated. I have a cheaper Onkyo TX-SR505. My speakers are so efficient that at a volume of 50 it is just too darn loud, no distortion at all. I have never been a fan of extremely high wattage as Mandelbrot proved there is more errors
with higher voltage/watts/amperage. I personally have found 65 watts to be sufficient for 90% of households. If it isn't, then the speakers probably are not too efficient. I build my own speakers, except for the Genesis II speakers I use for my rear surround speakers.