Questions from (possible) future X5 owner

[PLDubz]

I've been reading up on a lot of the posts on here and this seems like one of the more knowledgeable and reliable sites on the web.

I'm looking into buying a 2001-2003 X5, but I have a few questions about a couple of issues, mainly pertaining to reliability. The first step is deciding which engine size. I'm looking closely at either the 3.0 or the 4.4. I've read that the 3.0 engine tends to be more reliable, although I've read some differing reports on here, too. The gas mileage is essentially the same, and I would like to have the power in such a large and heavy vehicle, but if the 4.4 is going to cost me more in the long-run, that extra bit of power isn't really worth it to me. However, if there isn't a big difference in reliability, should I go with the 4.4.?

Another question has to do with price. From looking at ads, they range quite a bit and most of it is based on mileage. What's a fair price for a used X5 from '01-'03?

Finally, I've heard differing reports on the longevity of X5's. Is it a good idea to buy an X5 with over 100k miles on it? (Meaning will it last until I'm ready to upgrade in the next 5 years or so?)

Also, I live in the DC area and I was wondering if there was any reputable dealerships that have fair prices and well-maintained cars.

Thanks for checking my post out. I'd really appreciate any advice you all got for me.