Hello-Konnichiwa
Finally I found a Japanese paper on the original model of DRC, called REAS (relative absorber system) in YAMAHA, dated January 21, 2003. In this article, Yamaha said that DRC was first developed for A4 and after some research and development AUDI had a plan to adapt this DRC system to their RS4. But an issue of supplier occurred to give up the plan...
A couple of years passed by, with the help of KAYABA (the DRC shock-absorber constructor in Japan), Yamaha decided to cooperate with APA (Spain) to deliver the DRC system to AUDI. The center unit was manufactured in Yamaha Japan, and the shock-absorber was made in APA Spain.
Does anyone know about this APA Spain? I tried to search, but I could not.
Attached is the page 1 of the paper (Japanese with English abstract).
Some embedded Japanese fonts are deleted for upload, so the incorrect character may be displayed...Sorry.