Hello everyone! I currently own a 2003 Black RAV4 w/ the "Sports" Package, and I was wondering what are the best ways to increase either horsepower and/or mileage? -- In terms of cost and effectiveness (cheap vs. performance gains). I currently and have been using a K&N Air Filter for the past few months, and have been using premium (higher octane) fuel. However, I still feel the need for more power, but also mileage, if possible. I wanted to know what is, perhaps, the next step second up from a K&N Air Filter? I don't know much about modifying cars or improving them to make it faster .... maybe an exhaust pipe or muffler change or better tires (I dunno), perhaps? I just want to know what are least expensive & most effective ways to improve horsepower. Thanks!