Snell A/III. The biggest problems IMHO are now the mass loaded woofer which I suspect are all past their usable life spans and I have no idea how you’d replace today.
The driver quality, and crossover parts quality of the time just doesn’t hold up to modern standards. I think the mids and tweeters are certainly bettered by modern mid-range equivalents.
The magic IMO happened in the hemi-spherical baffle and floor facing woofer. I remember seeing hot glued arrays of electrolytic caps. Can’t imagine any of those are still in spec.
The closest for realistic imaging and bringing the recording acoustics into your room I’ve ever heard in a modern speaker is the Sonus Faber Stradivari.