Thanks guys, I too hope it will continue to run as it has been for the next couple of years.
Wally, I kinda agree with you... the harder you run the BMW cars, the better they seem to work. They definitely don't like to be used 'less', that is for sure.
smileyboy, I am not sure about the affects of the mile high air pressure on the performance, but at the sea level and going to LA a few times, crossing over 2000+ feet elevations, I have not seen ANY reason to be dissatisfied with the 3.0i performance. (and I have a 160+ hp zx14 sportbike, so I am no stranger to performance.) But there is no denying: 4.4i is more powerful and more satisfying in the end.
kloogy, there is no price that one can put on one's peace of mind. I spend a lot on other insurances, and my friends think I am an idiot for doing so. I like peace of mind, and if the above conditions that I described in my original post above were different, I would have probably gotten the extended warranty just for the peace of mind. But as it stood, I thought the odds were in my favor, and they ended up working out for me.
In the end, all that this thread is about can be simplified to:
A happy out-of-warranty X5 owner who suggests considering the car-specific circumstances before deciding on buying extended warranty.