Unless the JDM 4.4 box has the epicyclic 40/60, AWD and is the same length as the Aus. SVX box, which I doubt, It won't plug n play, the tail shaft will have to be lengthened. The Difference AWD makes the Aus. box about 3" longer than, either the US SVX or the Liberty/Legacy/JDM.
If you replace it with any other box, the TCU has to be changed, as the different AWD is operated differently by the TCUs.
Harvey.