How much will this whole project cost you?

And, here is a serious question: what does it get you? why is having an in-dash OEM navigation system that important to you?? I am asking since I don't really know what comes with the OEM nagivation system in X5.

My wife's 328i has navigation... I usually don't even look at the damn thing... I mean, I know where I am going during almost 99% of my daily driving.

I have a portable navigation also, that I have put inside the X5, and I don't even take it out of the glove compartment.

Is it the navigation? watching DVDs? backup camera perhaps?? (don't know the functionalities of X5's navigation system)... what is it that you will get for the amount of money you will have to spend to add a navigation system in?