The H&R drop is less than two inches. There is no noticeable change in ride though there is improved steering wheel feedback.

Increasing both unsprung weight and increasing distance from the bottom to the top of the tire negatively impacts both acceleration and handling. I don't know if OP cares but I thought it worthwhile to mention. Some low profile tires like Continental Extreme Contacts have soft enough sidewalls that the ride feels much the same. Unless one is tracking, coilovers don't pass my value equation of amount of improvement for total dollars spent. You can spend far less and have much better handling than can ever be safely used on the street. I have always questioned having suspension that had very many adjustments. The tendency was to spend too much time messing with adjustments when more track time would have been far more beneficial.

It all depends on what is important to the owner. Personally, I didn't want to compromise much comfort but was willing to for significant improvement in handling and performance. It took some trial and error and some risk but all were achievable.

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