Looking to replace all the tweeters on the above. The unit casings made of a combination of rubber and plastic, have degraded over the twenty years I have had them, to the point where they are pretty much falling apart, plus a couple of the grills have broken. My understanding is that the full units have been discontinued, although the grills can still be bought. Can anyone advise where if anywhere I can get hold full units or whether there is any other alternative?