My 4.4 sport (with rear air springs) has Bilstein Touring front (BIL-22119278, BIL-22119261), and Bilstein Touring (BIL-24026529) in the back. My X5 is lowered with the H&R HRS-293781 lowering kit. The ride is firm but not harsh - a little bit firmer than OEM that they replaced. The ride is excellent. I got them from FCP EURO.

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'05 E53 X5 4.4i, '97 E39 528, '07 E92 335i, '16 F86 X6M.