I just had the foam surrounds replaced on three JBL LE15A drivers. Shipping cost more than the job itself which was done by an authorized JBL repair shop. Certainly worth the cost. I thought that the foam was OK on my units (which had been stored unused for about 20 years) until I started to install them and found that the slightest touch on the foam caused cracks. I think you ought to refoam them just on be basis of their age. Like chicken soup...can't hurt. The passive radiators do not have foam surrounds, just treated corrugated edges, so they are probably OK.
I can't suggest any way to overcome the huge size except to get a bigger house, or a new... well never mind.
I can't suggest any way to overcome the huge size except to get a bigger house, or a new... well never mind.