PRS-350 question about transferring to kobo in Japan

It is my understanding that the Japanese PRS 350s sold in Japan use different DRM to those sold in other countries?
is this correct?

Is it straight forward buying a kobo reader and getting the books bought on the Japanese sony reader store over to a Kobo? (I have calibre)

.... as my wife wants a new reader and like the smaller size of the 350 (I understand the same size as the Kobo)

I just don't want to rush into it and find problems as I think the sony readers here are slightly different (????)

thanks