Quad 63 US Monitor rebuild?

One of my Quad 63s has developed a loud popping sound. My experience is that repaired Quads do not sound alike and I will probably have both rebuilt. Can anyone offer opinions on the Quads Unlimited or Electrostatic Solutions rebuild of the 63 specifically?
I debated buying some used Quads on AudiogoN last year and talked to some who rebuilt there own panels or had a panel or 2 replaced, figuring that would be acceptable and I could save some money. After speaking with Kent at Electrostatic Solutions, I learned that that is not a wise move. Usually when one or two panels are in need of replacement..the rest are not long for the same..not to mention the electronics and the need for an updated Clamping circuit.

I bought my 63 USA's fully restored from Electrostatic Solutions and was quite happy with the sound and service received. Kent is a super guy to deal with. Quite knowledgeable with the Quad build techniques and now uses the very same heat tensioning of the mylar that the factory uses. This makes a huge difference in the reliability of the panels and will keep them quiet much longer than when not done this way. His goal in the rebuild is to add some refinements and updates while keeping the factory Quad signature sound intact. With the USA's he was able to extend the upper and lower registers a bit, and add some dynamics over the stock 63. Well worth the cost and time to go with Kents rebuild IMHO.

This was one of the many resons I went with ES and was glad to give my business to Kent. You will be quite happy I believe. I cannot speak to Quads Unlimited as I have no experience with them, but they are highly regarded also.
I had my ELS 63's rebuilt by Quad Musikweidergabe in Germany - they bought all the NOS from Quad when they sold up, tooling, etc., and found them to be very helpful and a satisfactory job. They have also evolved a couple of improvements in remanufacture and materials, etc.