Just came across this:
http://www.nissan-global.com/EN/STOR...Y-MC92,00.html

There are two plants in Oppama, and I unfortunately didn't get to tour the one where the Z is built. They only showed us the one where they build the March, Cube, and Cube Cubic. It's interesting they say "The Fairlady Z is currently produced on the same line as the March". From what they told us, plant where is the Z is made is also where the Maxima QX (for Europe) and Infiniti I35 are made.