I still think a CSC, master etc should be powertrain, I think what is confusing is the lack of consistency between dealers, some replaced it under warranty others did not, which leads me to believe one of two things, either the dealers not replacing it are in fact completely incompetent or Nissan at some point changed the coverage on those parts, which consumer affairs should have the answers to, as well as the dealer, but some are buffoons, I know.
My best friend sold his s2k shortly after he got married, he still has a comptech supercharger kit sitting in his basement that was nerver installed....that thing cornered like a mother, but my 350z smashed it in a drag. It also had over 200k when he parted with it...