Good amps don’t sound different. I agree with most here in saying that’s a myth.
With efficient speakers like Klipsch, an Outlaw 5000 for your Front3+Surrounds would be more than sufficient for your ears to bleed.

run your Rears and Atmos from your AVR.
If you really think you need more power still (you shouldn’t) look at Emotiva, too.
Cheers.