Hi, guys. I have owned Quad ESL 63's can't tell you how many times I sent them back to the distributor for repairs. Then I bought Wayne Piquet 57 rebuilds and they have never failed. He lives about 100 miles from me in Florida, so I have had them upgraded and retuned a couple of times since then. I own a pair of 988's that have also failed panels. He says it is the Chinese glue that fails to hold the panels together. When all is working well, I still prefer the 57s, despite the limitations of range, image, etc. I have added Enigma Sopranino super tweeters and they have improved things. PK,s speakers play plenty loud and I have never blown them or tripped the protective circuit.
However, and this is a big one, PK is an eccentric dude with poor health habits who has had two heart attacks and is always late with stuff. He still has my 988s for repair and is several months late, but that being said, he is a guy with a tremendous heart and soul for what he does and would never screw anyone over. After all these years I consider him a friend who would never let me down, but I have know him for almost 15 years. His rebuilds are the best by far. A true master, but I fear for a meltdown. He's the best, but approach with caution. He has trouble with his website so call him direct would be the best approach.
I have never found a speaker to replace the sound of the 57s. If I were looking for a more mainline speaker, I would be looking at the Maggies.