K&N filters are just BS.

They are KNOWN to contaminate MAFs...the oil on the element solubilizes and gets into the maf...and they do so in a way that eventually they cannot be cleaned. (The MAFS develop and oxide coating that tends to insulate the sensor leading to lower sensed airflows. Eventually the car richens the mix.)

Take a modern BMW and take the filter out. Dyno it. you will find very little on the table.... 5-10HP replacing this with a K&N ***cannot*** give more than that... plus they let more dirt into the motor, silica into the oil and increased bearing wear.

They are a scam.