I have no specific experience with Mann filters. I have used the OEM BMW filters, and work at a company that sells filters for our own equipment.

Filters are not all the same. for two filters that are the same size and appear similar, there are often differences in the cage that holds the filter in shape, the filtering medium (durability, and filtering capability in microns), the pressure relief valve, and so on. All of these factors can impact filter performance.

When you hear horror stories about collapsed filters, dissolved filter medium, etc, you can not help but think of the cheap knock-off filters being produced without the quality control of the OEM filter.

Yes, I know Mann makes some good filters. That is true of many filter manufacturers. Many manufacturers make several lines of filters, with difference materials, and different micron ratings. The part numbers will be the same or similar, with little to differentiate the various products. A good example (not BMW) is the Motorcraft FL1, FL1A, and CFL1 (and whatever models they have added more recently) All have different specs, all fit the same engines. You get what you pay for.

In the scheme of things, filters are cheap, even from a dealer. I would buy only OEM filters, at the best price I could. At the end of the day, it is your call, your money, and your risk. Only you can decide.

Jeff

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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