firstly good choice r34 sedans are cool..... i would suggest go for one with the 3 gauge centre console.... the centre screen console is useless here in oz its all in jap and im sure it doesnt show electronic readings like boost etc...... i think it for the cd payer/gps but i could be wrong...
as mentioned above my factory boost gauge also died seems like a common occurance replaced it with a mechanical apexi one...... no mechanical issues i can mention however dont go on kms as often wound back......check for worn stuff like steering wheel, seats, oil leaks etc.......also as mentioned the centre console finish is shit but can be painted and comes up nice.......