@mglik A local dealer friend completed an impressive 100% restore of Quad 57s, down to every single little wood block, part, and component about a year ago. It seemed to be a more intricate restore project. He felt it was worth doing well.
After decades of exposure with all sorts of different amps and power ranges in a variety of different systems, and various speakers, he is overly familiar and has access to most anything. He has been running the 57s with low-watt 8wpc SET tube amps and fell in love with the sound except for the bass/dynamics, as I recall.
Last time I was there and saw the system, he later built custom subwoofers to cover any gaps, and seems to like them very much. He is so impressed with the midrange, enough to do whatever it took to keep these restored speakers in play on his main system. Interesting after seeing other capable speakers there, and he prefers his fully restored 57s now. Matching up ultra-fast subs would be key to-do, imo. You can reach him on Facebook, Marihart Audio. He’s semi-retired now, so go please go easy on him if you contact him there. See link, scroll down to see them. Scroll through gallery >> to see the later restored versions in Black, they look really nice in person. I need to get back up there to go hear them again!
https://www.facebook.com/pages/category/Audio-Visual-Equipment-Store/Marihart-Audio-745299465580983/