Many thanks to everyone.

I'm new to this site and and am very impressed with the enthusiasm and knowledge of the posters here. I don't own a car yet but I've learned a ton just reading.

So, as a current X5 shopper in the US I can confirm what others here have said

1) E53 X5's with NAV almost always also have DSP ... I've seen a couple of exceptions but they're unusual.

(P.S. I saw an 4.8is with no NAV the other day which I thought was very unusual)

2) The price of E53 X5's with NAV doesn't seem any different from those without .. the model, year, miles and condition seem to be more important factor.

Really appreciate the advice.

cheers
Dave