I owned a 4.6is for a few years. This was the "M" version of the X5 although they couldn't call it that. It had 350hp and 20" wheels. I picked it up used and I think it was over $75k new. Thanks to G Bush and the SUV tax write off, I was able to deduct half of the price off the car that year.
Ahh, the good old days. The X5 was a great car and I had no complaints about them at all. I outgrow the size of the car with my family of 6. The later X5's have a 3rd row, but it really is a compromise if you need the additional seating. At least for the 4.6is, I could chase my brother in his 911 from a stoplight and he could never shake me.