As a recent buyer of a X5 4.6is I know the market quite well after searching nationally for vehicles for 3 solid weeks. The market on 02's is from $33,000 for 50k mile cars up to $40,000 for 30k mile cars. The market on 03's is from $35,000 to $43,000 for the same mileage figures.
I bought my 02 4.6is for $33,500. It is silver, 53k miles, nav, new tires, mint condition.
I do not understand why sellers ask for the high $40's when there are so many really nice 4.6is's out there for sale well below their offering price. I had Vista Motors a BMW dealer here in south Florida offer me a blue 03 4.6 w 40k miles for $48,000!! Geee what a deal!
The pressure on the price is a combination of factors including gas prices, the 02's and 03's are all hitting the 40k - 50k mile range and becoming less desirable to their original owners and the leases on these vehicles are all coming up.
I found
www.Cars.com and
www.Autotrader.com to be good resources. A good used dealer is
www.LuxuryMotors.com more than a few X5's at reasonable prices. THey were offering free shipping a few weeks back.