I see you’re thinking about changing to a piano black plinth.
My wife insisted I do that last year because she doesn’t like the retro look of the fluted rosewood. It didn’t make any difference to the sound, but it sure looks good. I can post before and after photos if they are any help.
There’s an argument to be made that it would be better to keep the money to spend on upgrades that do improve the sound quality.
However, there is another option that my dealer didn’t tell me about until it was too late. You could get an old plinth sprayed with piano black lacquer. That may necessitate acquiring a second hand non-fluted plinth, but should still work out cheaper than ordering a new one from Linn. You may find that your dealer has a suitable old plinth lying around gathering dust.