I changed mine with my dad in under 5hours and installed a new cam cover and plenum spacer(it was apart anyway) Got the parts of ZMANALEX and used normal tools (make sure you have a low force torque wrench). I think I made a post of the work plus pics if you use the search viewtopic.php?f=64&t=47474 I asked nissan and they wanted £500ish for the job, just to note I had never worked on an engine before, so I recommend you try it yourself