Well here is a comparison you don't see everyday - going from a 65 wpc vintage integrated to a $10K modern amp that puts out 400 wpc. And doubles down to 800 wpc into 4 ohms.
I think the answer to this question is what speakers do you intend on driving that you would even need the Continuum 2? Also, while I doubt there are any upgrades you can do to your Onkyo A7 to remotely put it in the same league as the Continuum, depending on the speakers you have, you may find the Onkyo is all you need.
Again, it comes down to speakers as an amps first duty is to properly drive a pair of speakers.