An engine rebuild really isn't that big of a deal. But when you take into consideration the fact that most people who own 350z's either stay stock block or 'pay to play' you just won't find a rebuild guide.
IMHO, you could rebuild it and learn a ton, BUT seeing as you can't figure out whether you should or not based on your own past experience you should probably let a pro do it.
I'd say your best bet is to have a reputable local (rebuild/performance etc) shop rebuild for you but have you 'help along' (to learn some stuff).

 

thanks for the advice rrmedic and resmarted