Hate to bust your bubble bit there is no jdm mp3. The only thing close to the mp3 was the mazdaspeed familia. Now considering these were not obd2 it would be a head ache and a waste not to mention you would need the fsze as we'll
Also the chances of it being a msf ecu are pretty much zero considering only 203 were made
More than likely it's an fsze ecu and would still be a waste