After reading this I try to use one of the listed retail brands. Surprisingly, QT is on the list and are one of the less expensive places so I usually go there.
toptiergas.com

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'05 X3 3.0i Alpine White/Gray Leather/Alum. Trim
Sport/Steptronic/Servotronic/Panoramic
Prem. Sound/Staggered 18" Style 114 Y-Spokes