JDM ecu question

i was lookin on ebay for a obd1 today (doing obd2 to obd1 conversion) and i found a jdm obd1 ecu.... i know the jdm gsr's have like 10 more horse power than USD, is that because thier emission laws are different and the ecu's that are in our cars are more restrictive? or does it not have anything to do with the ecu? and if it is the ecu then... can i just plug the jdm ecu into the adapter thats for USD ecu's...? for example could i switch out my ecu for a jdm one and have the harness fit? and anyone had any expierience buying a used ecu off ebay.... seems kind of sketchy...

which ecu are u trying to buy

p75? not sure if thats it.... the obd1 ecu from a 94-96 gsr, jdm if that is better and is possible....i have a 97 gsr (obd2,p72)

you meen the p72!