To add in my fifty cents on the K&N filter discussion. Is that with my experience with them on my ride, they do seem to have better air flow and a slightly noticeable gain but I never had a problem with them. I just think it's better to have them, then not have them. It doesn't change hp dramatically but one thing I noticed is, that when I had a new car with clean oil after I installed a K&N a few weeks later, the oil is already dirty. I have no clue if that is harmful to engine but I think their filtration is not at 100%.