When I bought my Z 20 years ago, it was hard to come by. Only a few people knew anything about it.
The more popular OBD1 stuff was hacked back then and software was available to reprogram EPROM's. The L98, many of the TBI applications, and the Syclone are among the known ecm's. ALDL protocol was figured out and information was around as well although the engine specific definition files I linked to didn't find their way to public forums until a little later. But the 94 LT1 PCM with it's flash programming was still new. Hypertech had hammered away at the GM seed/key routine enough to build their Power Programmers and I believe LT1 edit had been produced by a couple of guys using information gleaned from several sources. But you're right that most of the guys doing tuning were either hard core or had a degree in a technical field. It was definitely a fun time to be involved in the hobby.