I have the Skyjacker coilover kit on my 2.8 CRD 2005. It was expensive and expected superior quality. Well, it gives a nice comfortable ride, but it wears quickly. The first rear shock failed quickly and had to be replaced. Now one of the front struts begins to make noise. The kit is clearly not resistant to driving on tracks (although I am always very careful and slower than anybody else). Further, the suspension is too weak for this type of terrain. Finally, the front struts do produce the infamous contact of the upper A-arm with the spring. And the rear springs come loose at full extension. So, I am not happy with this expensive product.
I have decided to have it replaced by an OME kit. A little less lift, but hopefully better quality!