There are plenty of ways to get a few more horses out of any car. The easiest are bolt-ons such as underdrive pulleys, larger throttle-body, larger MAS air intake, etc.With a small engine, the most important thing is to eliminate as many restrictions to air flow as you can. I have even heard of people taking their heads off to enlarge and polish the ports.Honestly, though, you will never be able to tell the difference in 10-20 horsepower. I know it "feels" better to have as much HP as you can squeeze out of a tiny engine, but it will make not a bit of difference on the road.The single biggest (and cheapest) thing you can do to improve your car's performance is to reduce weight. Hondas are already pretty light, but anything you can safely remove will help out. I have even seen people take out all the seats but the driver's. I guess if you were that serious, though, you wouldn't be driving a Honda.