The 188K differential among others (168,188,188L, 210 etc) are most commonly used in 6 cylinder engine versions of the following models BMW E90 320d Auto with 7591017 Diff / 320d Manual with 7591074 Diff / 320i with 188K Casing / 325i Auto / 328i Auto / 325i Manual with 7591015 Diff / 328xi Manual / 330i / 335i Auto with 7572055 Diff / 335xi Auto /.