You're right, my bad: Rating 2 is +2d6, so 3d6, so 3+1 Minors. Rating 2 suffices.
As for the wording in the book, I just compared the two PDFs I have.
Before january: "When activated,
each rating point of wired reflexes gives
you +1 Reaction (and accompanying bonus to
your Initiative Score), 1 additional Initiative Die,
and 1 additional Minor Action."
After january: "When activated,
each rating point of wired reflexes gives you
+1 Reaction (with accompanying bonus to your
Initiative Score) and 1 additional Initiative Die
(with accompanying Minor Action)."
As for Synaptic:
"The booster confers
a bonus of +1 Reaction (and accompanying adjustment
to Initiative Score), 1 additional Initiative
Die, and 1 additional Minor Action per point of
Rating."
"The booster confers a
bonus of +1 Reaction (with accompanying bonus
to your Initiative Score) and 1 additional Initiative
Die (with accompanying Minor Action)."
So the wording has in fact changed here, to make clear the mentioned Minor Action comes out of the initiative die, not on top of it.