4.0 Inline 6 engine swap with different year

I recently got into an accident and ended up damaging the frame/ chassis and I feel like it will be cheaper to just find a junker with high milage and just swap the engine and tranny. I have a 2004 Cherokee Laredo 4.0 i6. I found a 99 limited with a 4.7 V8 on Craigslist. So my question is how much of a pain in the ass would it be to perform that swap or can it be done at all without having to swap out a bunch of other stuff. Could anyone tell me what years other then 04 would work for a swap if the 99 wont work? Much thanks in advance

Your going to have to replace the engine wiring harness and ECM and maybe the BCM. I would try to find the same year and model.