The sound you like is largely down to the pleasing colorations of the cabinet and cones. New surrounds will not affect that much, if at all. If all you do is replace crossover components with somewhat better quality parts this won't change the sound you like very much other than to make it a little smoother and more detailed. You might actually want to be careful with caps as the really good ones can be so liquid it might actually take away some of the grain that is probably part of that vintage sound that you like.
Refurbishing 30 year old speakers
Looking for advice on refurbishing speakers. I have owned a pair of KEF R107's since new. They are still some of the best sounding KEF speakers ever made IMO, but after 30 years they most likely could use some refurbishing. I'm not hearing any obvious deterioration of sound, but over time, I might just not be noticing the degradation. I would re-foam woofer surrounds, change ferro fluid in the tweeter, upgrade the crossovers, and possibly upgrade wiring. I'm Interested in anyone's experience and results with doing this. Did the refurbished speakers sound better than original, or even sound different? Of course the other option is to go speaker shopping and buy a modern speaker, but I have grown accustomed to the vintage KEF sound.....My only real beef with these speakers is the use of the outboard equalizer device called the KUBE which runs in the processor loop of the pre-amp. Never been real fond of having an active device like this in the system but admittedly the results still sound amazing. Thanks for your thoughts.