?Since you're looking for max power I'd skip all of Topping amps. Their amps power ratings are pulled from the nether or just made up by the marketing department. I'd go with the Magnius since is offers a ton of verified power, top of the line measurements and great sound quality for $200.
Amir has measured the power output of Topping amps.
Topping L50 Review (Headphone Amp)
I know, I am looking for maximum power actually (without going top of the line). I think it is the A30 Pro and D10 from them if I am not mistaken, but their lineup seems to have numbers and letters all over the place at a glance. I am used to GPU numbers (bigger is better or at least newer)...
www.audiosciencereview.com