6 only runs with some hackery...

you need the kanji talk version of system 6 - that was modified by apple to run on the 145b because when the 145b came out there where problems localizing system 7 (which also just came out)

you can simply replace the strings in the system resources with the ones from whatever language system 6 you want.

and i also have the full 8mb ram in my 145b... these 8mb really make system 6 fly...