Hi , I have had these from new and while I loved the design I was not too impressed with the sound. I added a BL 2000 and it was imo a different experience.
To be fair to the speakers you have they are 25 years old and might have been well used, so you are probably not getting any thing like the original sound. The Mk ll version I believe was better but I have not personally listened to them.
If possible try to listen to another set of 8000’s to see if its a sound you like before considering refurbishing them .