Engine swap in a 2003 Range Rover
 

Does anybody know if you can swap a 4.4 litre to a 5.0 litre without changing a bunch of stuff (Modules/Wiring/ETC..)

I was considering this option as well with my lr3. Motor is fine @ 215k miles (knock on wood). Just playing the what if game. At minimum you would need a new ecu. The transmissions are different part numbers as well. From what I have heard the 4.4L is the more reliable less maintenance heavy version of the two. With the cost of LR parts (new or refurb) I think I would stay with the 4.4.