This won't be a popular recommendation but a practical one, try a Crown 1500, 525 watts at $450 new. I used one with ACI speakers, have A21 now with my Maggie's. Your speakers need power and you are on a budget.
buget used amp ?
I would like to find a nice budget amp to compliment an Adcom GTP-500ii, the amp will be power Thiel cs 1.6. The Pre Amp and Speakers will not be replaced. Thoughts? Thank you.