I think you're over thinking this tbh.
Looks really simple to fit to me unless I'm missing something?
Just take your time with it, remove your engine cover and it should be a fairly straight forward affair of removing a few bolts, adjusting the wiring harness, fitting the cover & bolting in place.
Did you ask Ian or Wasso? I'm sure they could help you with more info.
Link (post number 3 shows Ian's fitted JDM cover): http://www.350z-uk.com/index.php?showtopic=53872