Not in the X5, but I have sat in the 530i's 20-way multicontour comfort seats. Yes, I did know all the adjustments and I did adjust it to my heart's (and backside's) content. Amazingly comfortable and it's awesome!

But in general, sport > luxury. It's not like I had complaints with the sport seats, and I was just as comfortable. I still want to enjoy driving the car, without thinking "hmm, is that upper backrest at the best possible angle?"