So i was talking to this guy that owns a tuning shop here in Michigan. They specialize in Subaru tuning. Anyway, he told me that early ej20's like from a ver2 or 3 sti were "series 1" ej20's and that they differ from "series 2" ej20's in that the crank shaft is different and there are differences in the design of the block. Does anybody know if this is true?

 

I do know that the EJ20 has gone through a healthy number of "revisions" in the 12 years since its initial inception, but I don't thing that they were specifically divided into a "Series 1" and "Series 2".

I'm interested in researching this, and I'll post my findings sometime in the near future either in this thread or a new one. Sorry I couldn't be of more service at the moment.