This link helps describe the process of swapping the jets. If you go w/ just a filter 2 jet sizes bigger will usually do it for you. Filter, and a pipe is generally 3-5 sizes bigger. It will be louder around the intake, but too me it is not unpleasant. You could see 1-2 hp increase w/ 3-5 mph better. With more power available you wind up using less throttle, and you can see better mpg numbers. I think it is one of the best ways to make a little more power.
