So the problem is you want a 96/97 skyline for $15.5K? Most people will move on price if you are a serious buyer. If you are PMing them with offers like that on here, you might not get much response. If I were you, I would be going to some private sellers who are pitching their car around the 16-18K mark and see what they say. That price from what I know would be the bottom of the 96/97 market which could be why you are struggling.
As Dezz says, that is a GTR so if you are planning on making it look like that, get a GTR to start with as the GTST lines and "hips" that look good on that car, aren't on the GTST.