Thinking and need some advice..

[bagpype]

There are currently 2 x5s that I'm thinking about buying. The first is a 2006 4.4 with sport, premium, and cold weather packages (according to the owner) and fully optioned. It is a 3 owner car and has 102,000 miles on it. Apparently the "first owner put most of the miles on it". It is in pristine shape with black leather interior and no blemishes that I can see in the myriad of pictures sent to me. (Its 8 hours away so I can't pop in to see it). He will let it go for $16000.

The next is an 05 4.8 with roughly about the same miles on it and it is black on black. He will take $18000 for it. He bought it at auction (he's a wholesaler) and reportedly was a 1 owner car when he bought it from a dealer auction for his wife.

I will look into maintenance records tomorrow when the dealers open and will have a PPI done by an indy if I decide to go with one. I am trepidatious with these cars for 2 reasons; 1 being the most obvious is that they are high mileage cars and I don't know either of their history. 2, I do most of the work on all of my cars and have had Porsche, Mercedes, and many VW's but have never had a BMW.
My questions:
Armed with the knowledge that I have provided in this post, are either of these cars worth the price? Which one seems like a better deal (if at all)?
With regular maintenance and the wherewithal to wrench on my own cars, can I reasonably expect these to last another 50 or 60k miles without some catastrophic problem? Before you say it, I know that some cars are better than others and that some people just get unlucky but I am asking about the general nature of these particular x5's.
Thanks for any constructive responses.
Adam