Reviewed By Peicheng C (Easton, PA) Reviewed for a 2009 Mini Cooper —5/18/2017 8:36 AM
I had a K&N filter but I don't like the color (dark, looks not very clean). I replaced it with a green filter. I can hear the air flow hissing sound while driving. For me it's not a noise. Instead it sounds very smooth. I still have not got the chance to figure out if it improves horse power and/or gas mileage though.