The "Nielson" car as we call it was built by Seikel Motorsports in Germany for the Honda backed factory race efforts in Europe in 1993-4 and raced by a Danish guy, John Nielson. This car raced at the 24 hours of Le Mans in 1993 and lived to tell about it.
It was retired at the end of 1994. See article for some details and fun English flavored commentary. I picked up the car in 1999 from Herr Josting, an NSX fanatic in Germany who bought two of the original three cars made from Seikel or from someone at Honda Germany that wanted to clean out the unwanted "junk" in their storage garages. Build details and the cars exact history are unclear since Herr Josting died of leukemia right before we completed the sale. This car is currently at AREA 51.5 being restored and improved upon here and there. Pix were taken at NSXPO 2003. Expect some of the factory race parts to come to market soon.