I believe that there are different specs for various diesel exhaust fluids, all designed for selective catalytic reduction. BMW's requirement is for AUS32, according to the owner's manual, which is 32% acqueous urea solution. Any fluid that meast the AUS32 spec would be fine. The spec is controlled by ISO and DIN standards.

Some diesels use AUS32 at 3-5% of diesel fuel burned, not at 2% as Cummins has published (but it depends on duty cycles).

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue