I would be more concerned about rust than mileage,bodywork is costly and some owners prefer to add lowering kits, spacers,etc etc and ignore the important bits !!
Nice looking car,had one the same,great car had to get rid due to needing back seats,but still cast lustfull eyes over them,especialy in white,good luck .
Went from a 370 GT Edition back to a 350 and in some ways liked it better,particularly less tyre noise despite having 370 wheels,missed the extra grunt of the 370,and couldn't face restoring the rear arches on the 350 so wont be going back to an old car .
Seems some of the Nismo's had an fluid leak of some kind that got into the clutch housing,but no idea regarding the GT cars,that was the reason i went Auto last time.
I too have been thinking about getting back in a Zed,sold my 350z about a year ago and bought a 17 plate TT with 15k on it this spring as i needed an occasional back seat for grandson to nursery run.I have only done 2.5k since getting the Audi and had to have it recovered for failed water pump,so much for German engineering.
A few years back i had a GT Edition model 370 auto which i enjoyed having but due to work etc couldn't use it much.Question is should i try manual this time? Is the gearbox action similar to the 350?I had also heard of clutch failures on the mk1 Nismo at low miles happened occasionally was this also true of the GT.