I would also agree to refoam and not try and replace the drivers. I know Roy would also for some drivers write - , 0 , or + on the back of the drivers as he would then match the drivers and only include the same matched drivers that he individually tested. So for instance both tweeters would have the marking - on them not - and then +.
I've owned the Europas, Callistos, Eos HX and C1.5 and they were all excellent speakers. I still have the Callistos and spare woofers for them. I've since upgraded to full range speakers but the midrange, detail, soundstaging and realism of the Green Mountains was first rate. I also enjoyed speaking with Roy on many occasions although I really didn't understand all the physics. I always felt like I just had a one hour physics class when the call ended. He was such a great, knowledgeable guy. I was in line to get the EOS ribbon tweeter model but unfortunately that never happened.