Was not familiar with these so I looked them up. Beryllium tweeters, 84 lb, quite expensive speakers in the early 80s.
Might be someone here who has an idea about how to get your PR's fixed. GordonW is speaker repair guy, you might send him a message. Or better yet, post this over in the Speakers forum.
The trick is going to be getting the right cones in terms of material, stiffness and most importantly, mass.
What exactly has happened to them? Can you post some pics?