So I bought myself a 2004 Range Rover with 70k and in fairly good condition as my '02 RR died. Some minor things to fix, already fixed the oil filter housing mounting using some rubber stoppers and bolts from Lowes to replace the wire holding it when I bought it. I am currently looking for the temp sensor/module that sits on top/behind the radiator fan as that is totally missing but the fan works and it is winter time (sort of).

Now I want to upgrade the BMW Nav. computer from the MkIII to the MkIV so my question is which MkIV to get, do they have differences with regards to years etc. or will any MkIV fit ? I did search on here but couldn't find an answer.
Thank you in advance.
Aynsley