@Ciemnika: I prefer the black case, so I bought a black HHKB Pro 2 and put the white keycaps on it. Later, I switched the modifiers to blank black and blue alphanumeric keycaps with black legends from a Topre Realforce keycap set. For a bit of accent color, I use a blank red Esc and a red arrow key for Fn.
On another HHKB Pro 2, I installed 55g domes from a RF donor board (which now has the 45g domes from the HH board). However, I prefer the 45g domes in the HHKB.
I like the downstroke thock of Topre switches, but I don't like the return stroke clack, so I have installed silencing rings on all my Topre-switch keyboards. I also lube the stabilizers and switch rails with Superlube oil.
These are just some thoughts on some things you might wish to try with your HHKB.