I wouldn't paint it unless it needs the paint, as that would basically kill it as a mint specimen.

As for the CF card, a re-celled battery and more ram, it's a question of how deep your pockets are tinker-wise, or else whether you have an actual use for the thing. In my case, I had a use for it: my 2300c now goes with me in my briefcase as a writing platform. I leave my 12" G4 PB safely at home, and find that I write faster on the 2300c than on the G4, due to less distractions.