Without any other modifications the gains will be very minimal. Some companies claim up to 15-20HP gains on just the CAI but I dont believe it. I bet you will get 1-6hp gain, maybe see a tiny difference in fuel economy and it may make engine sound a little louder.And I do not agree with the 1st answer saying it's not worth modifying this car. I believe that the 07 Accord's 4 cylinder is the K24 engine, which is rated around 200HP and is a very, very popular engine to modify and is Honda's newest tuner favorite. I have seen in magazines cars that have this engine and are pushing 400HP and more, and getting insane 0-60mph and 1/4 mile times, so go for it man!!