I installed the K&R lowering kit several years ago. You can see the results in my album if you want. The kit comes with shorter springs and adjustable links. It has been trouble free. I understand the capability to change software to lower an X with airbags on both ends. If I had one I would still see if adjustable links would get me where I wanted to be if lowering was my only goal.

I had heard about some E46s breaking springs when it was time to rebuild the suspension on an E46 I had. I never got the sense it was that widespread and didn't replace the springs. They were fine at 168,000 miles when I sold it. I guessed the issue was more likely a result of very bad roads or ignoring speed bumps rather than corrosion. I have not seen evidence that problem carried over to E53s and in all the discussions here about rebuilding worn out suspensions I have read I don't recall anyone recommending springs should be replaced nor have I ever seen a suspension rebuild kit that includes or suggests new springs even be considered.

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