You would need to bring everything from a working ADM P5, over to the JDM SP20, including but not limited to.
wiring harness, ECU, Injectors, throttle body, TPS, Mass Air, IAT, Speedo Cluster, Fuel Pump and Fuel level unit, You would need to install ABS sensors on all 4 corners on driveshafts that do not have sensor rings. Key Fob module, Air Bag module, fuse panel.
You could better use the time to build a Zonda R, because at the end of the day, nobody would give a s*** about a 4WD 10 year old car, imported and registered on the continent of the United States.
i would like to add that if you say that the car must be OBD2 to import, you would need to go to Japan for two weeks to convert the car, then fly back to petition your import.