Don't just blithely assume you can drop in UTF-8 and that
it will "just work."  There were a number of discussions
related to UTF-8 email at the IETF meeting this week.  The
consensus was that we haven't achieved interoperability yet,
at least not to the level everyone would like.  I expect
there will be one or more internet drafts coming to life
to address this.  You might want to review the videos
from the emailcore and sml WG meetings.

I will try to find some time over the weekend to take
a look at your diffs.

--lyndon