From some old correspondence with Yasu of Team JAPUMP!!! circa 2010:
SimDrive (Namco System 22, not System 21) uses actual body of Mazda
Eunos RoadStar. It was actually developed and did appear on AM show, but
not released to the market. See attached photo (from page 135 of the
November 1992 issue of the magazine Gamest, covering the 1992 AM Show).
Image:
(Thank you for mirroring scan on the wiki)
Translation/transliteration of text, but not captions (by Gridle):
A hyper driving simulator "Simdrive" implemented on the Namco original
visual system "System 22". Newly developed high performance graphics
machine "TRĀ³" enables pictures and textures on polygons, as well as
shading, allowing for more realistic graphics.
It is confusing to tell the difference between SimDrive, "Eunos Roadster
Driving Simulator"
http://www.system16.com/hardware.php?id=833&page=1#2687 and "Ridge Racer
Full Scale"
http://www.system16.com/hardware.php?id=833&page=1#2693so it looks like the chronology goes:
1. 1990/09 - Eunos Roadster Driving Simulator (released - for driving schools) -
http://www.system16.com/hardware.php?id=833&page=1#26872. 1992 - SimDrive (prototype) -
http://www.system16.com/hardware.php?id=536&page=1#13123. 1993/4 - Ridge Racer Full Scale (released) -
http://www.system16.com/hardware.php?id=833&page=1#2693Eunos Roadster Driving Simulator (Namco/Mazda/Mitsubishi Precision) is
actually released (only to driving schools, not for arcades) in
1990/09.
So technically a final fix is to move SimDrive from Namco System 21 to
System 22. Wikipedia Japan has this correct.