Considering X5 Purchase

[scottb]

I'm a newbie to this board (though active on the 911 board). I'm considering the purchase of an X5 3.0 with a navigation system. I have lots of questions....

1. Are there any model years that I should not consider? (i.e., known to be bad?)

2. I've heard that the navigation systems were changed at some point along the way. What was changed, and why?

3. Are there any known faults in the car that runs through all of the model years?

Any answers to these questions and/or general advice on the purchase would be appreciated.

Thanks, guys!