97_sti

Is there any engine that is 95-100% compatible with my 97subaru sti. Spun a rod bearing now recently rebuilt seems to have some sort of lifter problem in the head now. It is and ej20kdw7pr. Would a new ej20G swap over? Heard that I'd need to the the ecu re pinned to work. Need help! Please and thank you. It's is jp spec as I'm currently in Okinawa Japan. Surprisingly not to many ej20k floating around junkyards here