I can't remember exactly what it looks like but there is a lug/tab that lines up on the rack and coupler that is exact center. I think you could even put a vice grip on it to hold it there when doing an alignment.

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