Interesting read. I just installed the BMC filter in my '07 M3 which already had the EU filter. I noticed the BMC filter was at least 10mm short. I haven't noticed any change to the induction noise, but with the BPM Sport aka Benvo tune, I do feel the car rev much freely. I just feel it ... don't know whether this is the placebo effect. But I am enjoying the new found driving experience.
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F86 X6///
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