You turbo'd?gained 27whp in my 06si with one.
Not just the filter, replacing the whole air box with the K&N air charger, or w/e you call it, I've heard it called many dif thingsare you talking about the K&N air filter or the K&N typhoon short ram?
Yeah that's somewhat what I'm planning on doing. it may be a while before I have the money to replace the header and get the whole catback that I want, but thats my goalIt's a very good start. Alot of people start here and then open up the exhaust side of the engine with a header and catback exhaust. Doing one piece by itself you may not feel a difference. Doing all three will make a noticeable difference and they complement each other very week. Good luck!