Hi,

the harnass you are looking for, to retrofit nav in your X5 is:

BMW part number: 61 12 0 302 345

If you are looking for a compleet retrofit nav for the X5 PM me.

I got:
16:9 unit
MK4
wiring harnass
GPS antenne
mounting stuff
BM54 Radio

including the install instructions.

gr. Appy