Hi Mike
Have just re read your posting and there is not much that has not touched the sides of your knowledge base.
I imported many of the 240's and a few 260's under the non remittance scheme whereby if you had some genuine funds, convertible assets or an inheritance overseas you could use these to import a car. This was all in the 70's before it came to an end and the detail required was enormous - i remember arranging to sell a young ladies grand piano in S Africa as she could not bring it out. It gave enough for she and her hubby to import 2 z's which I converted into NZ cash for here after the mandatory 6 mths ownership period - in fact they never left the showroom and we shared the profit over and above the import price 50/50.
I had a lot to do with Shekhar Mehta who was a Kenyan and won the E African Rally several times and rallied a 180B SSS (it had a secret ali block) in the NZ rally. His knowledge on Z's was vast and he became the FIA Rally Commissioner and died in 2006. I still use a lot of Z parts in racing cars now days such as rods, pistons, rings as they last even in standard form. I also had a bit to do with Timo Salonen and his Datsun 160J SSS when he won the NZ Rally in 1980 which uses similar 180B/Z parts.
I also made the fibreglass f and r spoilers for Z's in NZ, as Nissan had some for the E African cars but not as a parts purchase. I owned a motor Company that owned part of Nissan NZ so was close to the action.
Hope I can help out with more info later. I have some old competition parts manuals for Z's. Chris Read - Arrowtown.