Just wanted to clarify on some false speculation in here. It's a couple years old and you guys might have figured it out, but I can say with relative certainty that despite having been yellow, Revmaster T's Group-A car is not the AutoTech E30 M3 that raced in the JTCC (All-Japan Touring Car Championship) in the late 80's / early 90's. AutoTech never campaigned more than one E30 M3 and that particular car still resides in Japan. Furthermore, the AutoTech E30 M3 saw its first JTCC season in 1988. However, according to the information you received from Schnitzer, your car wasn't sold until 1989.
Now all that said, I might have some information about your car you might find interesting. It looks like your car did infact participate in the JTCC under the ownership of Kevin Wong. He raced in the 1991 JTCC season (maybe more) with team "OVER TAKE". Here is a link to some race results and his car and name come up. 18th place finish, but he is there!
1991 JTCC Results - InterTEC Race at Fuji Speedway