What is better for the svt focus, a k&n replacement filter, or an aem cold air intake? After reading about both upgrades it seems like the k&n @35$, with a claimed "2-4% hp gain", would be a much better buy than the aem cai @230$ with a 5hp gain...they seem to increase performance equally but at a huge price gap, so which is the better buy? Which gives you the largest performance gains? If the gains are the same with both products why would anyone ever purchase a more expensive aem cai? Any help here would be much appreciated.