As long as you currently have the navigation unit, there shouldn't be too much to do. You might need a custom face plate if there isn't one pre-made for the X5. That should be about it.

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Lemans Blue X5 4.8is
Dynaudio
Diamond TDX 12" subs x 2
Xtant X604 x 2
Xtant X1001 x 1
VST 7" LCD x 2