The kit I used was a GB 8017 and it was probably from RockAuto, that's for the M54 so maybe check if that works for you. Your choice if you want to use the silicone compound or the regular black for the rail.

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1988 325is (purchased new) sold
2004 X5 3.0 2005 X3 2.5
2008 X5 3.0 (new to me)