usdm&gtjdm

Hey all, What would be needed to swap a failing USDM K20Z1 to a JDM K20 ? I would imagine I would need a new ECU, but is the wiring different? Axles? Tranny? I am looking to replace a dying K20Z1 in my ride. How hard would this be? I only ask as I am finding it to be a bitch to find a K20z1...