I think on civics in general bolt ons like air filters and stuff don't do much. I hang around on a 7th gen board and thats rule number one to tell new people before they waste a lot of money.

I suspect honda has it tuned very well and you won't get any extra MPG. It may even decrease it.

Just my opinion though. If you can find one and you realy want to do it I would be very interested in your results.

My hydroponics experiment

You ever notice how hard it is to lip read cartoon characters?
"Crazy is what the sane call Delta Flyer"