At what point is "builder" status conferred?

In the thread I started about the 700 mile commuter airplane someone
suggested getting a used Long-EZ. (I would like to point out that my
dream of flying began the day I was much younger when I saw picture in
a late '80's National Geographic of two EZ's and a Viggen flying in
formation so Rutan's designs are dear to my heart.) I started looking
around and found several Long-EZ's for sale or sold recently that
could be had very affordably. I also noticed a number of planes that
would require work that varied from as little as needing an annual to
others that needed an engine/prop to others that were only partially
constructed.

For a homebuilt, is builder status conferred on the person who buys
the kit/plans and starts it or if I buy a partially built plane and do
the rest am I now the builder of the plane?

In addition, what happens if I buy a VFR plane and then replace the
engine and avionics and make it a IFR platform? Am I the builder for
the parts I put on it or does the fact that I bought an already
airworthy plane make it in essence little different than buying a 172?

BTW...I'm joining EAA this week. I have a strong feeling that a lot
of these answers (and a whole bunch of questions I haven't asked yet)
are available on their members only website. I've already told my
wife that Kitplane is to never be recycled but it is also clear that
other resources are required before I spend a dime on anything.

As an aside, thanks for everyone's responses on all these. I
appreciate that nobody complains about my lack of knowledge and that
the discussions here remain civil (thus far, anyway.) I learned a
good deal just reading the discussion following my previous post.