Do the 3.0d's have 4 corner air? If not, the upper strut mount is part #1 in the diagram at the link. But there are other dampers in the assembly as well. No idea if any of them might be responsible for a shimmy though.

Guide support/spring pad/attaching parts | BMW X5 E53 X5 3.0d M57N Europe

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2005 X5 4.4i Build 04/05 Maintenance/Build Log
Nav, Pano, Sport (Purchased 06/14 w/ 109,000 miles) (Sold 8/15 w/121,000 miles)

2006 X5 4.8is Build 11/05 Maintenance/Build Log
Nav, DSP, Pano, Running Boards, OEM Tow Hitch, Cold Weather Pckg (Purchased 08/15 w/ 90,500 miles)

2010 X5 35d Build 02/10
Nav, HiFi, 6 DVD, Sports Pckg, Cold Weather Pckg, HUD, CAS, Running Boards, Leather Dash, PDC, Pano (Purchased 03/17 w/ 136,120 miles)