I'm planning to hook my Empeg up to my car's ECU to control timing, adjust fuel delivery, and control the limiters (speed and rev). Should be a fun project. Has anyone done that yet for any model of car?

This has been discussed, but I don't think anyone has a completed implementation of this kind of project yet.

Search the BBS on variations of "OBD2", "OBD-II", etc., for threads on this topic.