Hrmm.. this is quiet interesting.. I have been told that to do a ECU reset (at least for a R34 GTT), disconnecting the battery dont do crap this is due to something about an open circuit.
To reset the ECU someone has to actually "plug into" it to reset it and have been told that this cost ~$80 ?
I have read alot of articles, etc., but has yet seen a car in real life that the prescribed reset ECU procedure (by disconnecting battery) works.