Originally Posted by SROC5
looks very similar, if not exactly like the K&N filter. Also, it should be noted that these likely don't fit in the air box perfectly.
The Macht Schnell filters have been on the market since early 2009. Though the pictures below are of panel filters, the same design goes into the different design of the S65 Filter necessary for the M3.
Most cotton-gauze filters will share the same characteristics - cotton, oil, mesh and rubber/polyurethane construction. The MS65B40 goes a bit further. We'll start with pleat depth.
The MS65B40 filters are made up from an 8-layer construction with an approximate 1.5" pleat depth, the newly released versions are about 50% deeper. As reference, K&N & aFe's depth measurement is only about 0.75". Pleat count & depth play very important roles in filtration - while providing maximum airflow, in a safe and efficient manner.
The Macht Schnell MS65B40 are an 8-layer construction, twice as many cotton piles as K&N and aFe. This allows more filtering and greater oil saturation for dust collection.
An important factor not really talked about in the past is the bleed area or "wicking". This is the urethane bleed that is soaked up by the gauze, reducing the surface area of the filter and limiting airflow:
Here's an example of poor wicking on a popular panel-type filter:
The Macht Schnell filters have very little bleed, keeping the wick area to a minimum and permitting maximum airflow:
The MS65B40 filter is a specific
e9x M3 filter and set to be the best filter on the market for your M3 - not a "one size fits all" application.
Is it the cheapest? probably not. The best? Without a doubt. Rest assured - you are getting the best stock-replacement filter for your S65's powerplant.