I use a pair of Parasound A21+ to drive the HE6 and Susvara. They're rated at 1100wpc and measure in the real world at about 2000wpc. Yes, they like powerful amps but there's a fact in the way and that is that you can not feed them all of that power. It's not an opinion. I would put the pair of A21+ at like a 96/100 and the 2023 Soloist GT at 95/100. I've tried hundreds of thousands of dollars worth of amps to find things that drive them well and almost all speaker amps I tried up through around $6000 were no better than a mid-fi headphone amp. What I'm trying to get across is that power figures mean literally zero, it's much deeper than that. Damping factor is usually pathetically low on speaker amps as is channel separation. The benefit the high power speaker amps have is massive power supplies that have a far lower power droop with load than almost any headphone amp and that's great, but they almost always fall short in every other metric making the raw power irrelevant.