RACQ checks are pretty shit imo.
sorry but i know alot of people who have had ther silvias and skylines done and they dont pick up the simplest problems.
eg oil leak from turbo. coolant leak. cracked manifolds. sump leaks. wheel bearings.
mostly they will only pick engine oil leaks, brake pads and tyres. they only do major bits...
i recommend take a trusted mechanic who understands the cars. jack her up go fully over it..
one way to check kms is to look at the door service sticker. or the dock kms reading. but most of them are ripped off prior to making it into the country. also check the interior condition handbrake condition/steering wheel/pedal/seats/carpet..