Check your sway bar links. They clunk when loose or bad, either one (or both).

thrillcat, buy the arm with a new bushing pressed in. Bimmerworld will even press in Powerflex bushings for you if you want (for a price). Don't forget the little ball joints that bolt to the thrust arm. Tie rods should be checked too. Your front struts are probably toast if they haven't been replaced by now (bounce test doesn't work, but I can assure you that midwest roads and >100k miles have done them in as mine were shot at <90k miles). All of this individually would require an alignment so I prefer to tackle it all at once. If you do it yourself, torque the thrust arm and control arm bolts with the suspension at normal ride height.

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Kirk
Las Vegas
2016 X5 40e Mineral White/Black Dakota Leather, ZLL, ZCW, ZDA, ZDB, ZPP, multi contour seats, rear side window shades, HK stereo
2011 E90M3, 6-speed manual