do not put a cold air intake in. just replace your factory filter with a high flow filter. when you add extra piping you are making the air travel at a longer distance, you are losing pressure inside of the piping creating a loss of horsepower. not to mention where exactly are you getting cold air from. it should be called a cooler air intake. use your money to do more positive things to your car. like royal purple oil, pulse plugs, k&n air filter, helix power tower throttle body spacer (if available),and a good programmer. with that combination you will increase hp by about 15-30 and mpg 5-10. i have done this exact set up to my 2002 v6 firebird. the results were very noticeable. i added an exhaust for better air flow. but , i wouldn't suggest spending money on an exhaust system for a honda civic. maybe an axel back system.