MAF can be tricky to diagnose, sometimes you need to try a known good unit to verify. You could try cleaning the IAC/ICV again with some air intake cleaner(maybe rinse that with the contact cleaner) NOT carb cleaner. I would say the fuel trim codes more likely point to a vacuum leak(maybe CCCV) than a bad MAF or IAC.

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