The trick, at least with the seats in my F85, was to fix the the height first, and then everything else falls into place. In fact, I just followed the instructions from this guy at the M driving school:
Pay special attention to setting your height from the headliner. In an X5, you should be seeing quite a bit of the hood when you're in your natural driving position. Before I adjusted it, I was sitting entirely too low and way too far back. It's going to feel dorky if you're used to a more "laid back" driving position, but after a little while it starts to feel way more natural and correct.
I was NOT happy with these seats originally. I found they had bad pressure points, they'd make my right leg go numb, etc. Using that video as a starting guide and then making minor tweaks here and there made a WORLD of difference. Now I find that the M seats, which most people regard as overly stiff and non-compliant are actually
very comfortable, and I enjoy them even on long drives. Give that a shot.