FYI, the thicker the spacers increase stress on the suspension. The key is to fill the wheel wells. On a 2002 4.6 with 187 rims 275/40 and 315/35 tires and 20mil spacers the tires are out as far as they can be without clearing the fenders. I did the spacers first, it still didn't look right. After added a lowering kit that drops the front and rear about 1" it looks great. Lowering the back improves the look some. If your 2006 has the suspension level links that is very easy to do. To drop the front which is when it really looks good, you will need lowering springs. The H&R kit results in a little bit stiffer ride but not that much. Whenever anyone asks if spacers effect alignment it generates many posts on both sides of the issue. Because of the cost of tires I aligned the X5 when I added spacers and when I added the lowering kit. Each time the the before specs were out. That was according to the shop. I didn't tell them about the spacers or that I had lowered the X5 but all wheels were out of spec both times.

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X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas