Below are pinout diagrams for the 3VZ-FE ECU and the 94+ 3S-GTE ECU. I made the 3VZ-FE pinout diagram because I couldn't find anything similar and all the 3S-GTE pinout diagrams I've found only list the ST205 pins and not the MR2 specific pins for used power steering and traction control.
I hope these diagrams may useful to others, please let me know if there's any errors!