To achieve an alignment that is best when driving, the added weight makes sense, though 450lbs in most cases would include a couple with 2 good sized kids and a suitcase just under the big charge for checking a bag. That's unless they only eat at MacDonalds.

Loading it up to be sure it doesn't rub, unless it rubs when you lower it should not be necessary as the system should compensate for any added weight.

Any lowering will change the alignment specs to some degree. To be sure how far you are lowering the X, you should drive back and forth a couple of car lengths and stop abruptly in both directions to let the suspension adjust each time you make a change. When you get it set where you want it you should get the alignment checked

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