Well since they included the ECM, wiring harness etc. It should be a relatively easy swap.
However, you do realize that the engine is a 3-cyl right? It's a 660cc, 3-cyl turbo from a Kei spec Jimny. It puts out a little less hp/torque than the 1300cc engine.
The tranny looks different too; a little smaller and less robust as it doesn't have as much power going through it. I wonder if it even has a 5th gear.