Help with information on KEF 105.4 classic speakers

Hello all:  I am a new member and this is my first post - hope I get some good information!  I have some KEF 105.4 speakers that I have had since new (time flies, but I think I bought them about 1982).  They are in outstanding condition (with the exception of a "ding" at the bottom front edge of one of the speakers.  They only get played about once a month. I still have the boxes, instructions, and brochure, and have considered selling them, as I have a renewed interest in audio and home theater.  I'm not an engineer, and don't fully understand the electronics, but I happened across some information about how people had "upgraded" the capacitors (?), and other aspects of these speakers.  I am hoping that some expert out there would be able to give me some advice about what might be required to update them.  On the other hand they are original, and I don't want to mess with the insides and get no improvement, as when I do sell them in their original state and I would like them to go to a home that can give them the care they might indeed need.  I live in the San Fransisco bay area.
Thanks for any help for a neophyte!