I moved to a D'Agostino S250 stereo amp and I love the match with my TAD's. I bought a used one for ~$21k, which squeezes into your budget. It has grunt and bass foundation, without doubt, but it also surpassed the Luxman in terms of musical info and soundstaging, just being more convincing overall. And its midrange is very good for any amp, and the best SS that I have experienced.
I don't know the Wilson Sasha 2's, but my general impression of Wilson speakers is that they, too, benefit from a warmer rest of the system. I know they are famous for unforgiving impedance curves, which probably exacerbate the issues with the Luxman's bass. D'Agostino could address these concerns nicely.