For the record on the Bilstein HD's, I've had now (1, 2, 3, 4, 5, 6, yup) 7 vehicles with Bilstein HD's all the way around. I have noticed that sometimes the Bilstein HD's need a few thousand miles to settle in. I recall one set that was installed that I thought I would have to remove ('89 Volvo 740 sedan), but the more I drove it, and the more aggressive I got behind the wheel with it, the more they smoothed out, and in a couple thousand miles they really settled down and behaved quite well. That particular car handled quite well (it had other mods done as well).

But they've been on the Suburban, 4 Volvos, a BMW, and a Jeep and I've recommended them and put them on many other friends vehicles, and they've all been excellent. When the X5 needs new ones...it'll get bilsteins.