Looks like a mix of JGTC and Super GT years (bottom Epson nsx is definitely Super GT).
Sorry, no interior photos or anything like gionc but maybe they might help regardless. You may also want to look up other cars from the era like the DOME/Avex, Raybrig, PIAA, or Takata cars.
http://www.kiibou.com/feature/gt1998_r5/
http://www.flickr.com/photos/amika_s...7600057734656/
http://www.flickr.com/photos/amika_s...7600054591484/
http://www.bespokeventures.com/blog/...ugen-jgtc-nsx/
You may even want to try the Super GT website. They still have some archival stuff from the JGTC years. You'll have to search through them but maybe you'll get lucky. Click on the Round/Year you wanted, then pick either "Practice", "Qualify", or "Race Review". Some have pics, some don't.
http://supergt.net/supergt/history/jgtc_index.htm