I bought a Power 1000 intake for my civic. It looks really cool. The intake sounds nice and deep when I floor the gas, even though I still have stock exhuast. It has a resonator built on to the pipe and a spiral filter that they say you get a 5hp increase from, but lowlife is convinced that bolt-ons do not add any performance on the v-tec e engines. I disagree with this view. I believe the bolt-ons do improve performance just not as much as most people would expect and you will not get much of a Horsepower increase. What you will get is a quicker throttle response and better gas mileage. Which in my opinion is better performance. I can vouch for the fact that I do not have the press the accelerator as much to get the same acceleration as I did before and it sounds decently deep inside the vehicle when I push the pedal to the floor mat.
But I liked this option because I may have wasted my 90 bucks on this intake on ebay, twice as much as a cheap one, but also it has a sticker, looks and sounds good, and it gave me a unique intake. I have not seen this intake on anyone else car and I get a lot of questions and comments about it. It retails on their site for about 300 I got it on ebay for about a 100 after shipping.
I also would suggest energy suspension control arm bushings, the black ones not the red, the red are noisy.
Get your ball joints and struts done when you put on the bushings and suspension will be smooth. Change motor mounts, all four of them. You can get energy suspension bushings for the front and rear mounts, but be cautious because they do not fit one of the aftermarket front or rear mounts. I had to cut mine to fit one and it was a BlTCH, took like 4 hours of cutting with a gerber brand knife(really sharp) and the vibration from my engine was pretty bad at an idle.
I have been trying to get a Xtune cat-back for my cah(not the spyder one), because it is reasonably priced about $150-175 and it is hi polished and does not look like a tin can ebay cat-back, but it has been on back order for 2-3 months from japan at every site that carries the cat-back.
I got a 4-1 header for 75 bucks but have yet to put it on, you can get a dc 4-2-1 header but its like 3 to 4 hundred dollars and won't give you much more performance than the 4-1 header unless you put a turbo or something with a major hp increase on your cah. Get a high performance cat on a down pipe, got mine for like 55 bucks, make sure it says cat on the description not just a test pipe made to look like a cat or you will have check engine light and will not pass emissions. Its hard to find a decently priced real cat on a down pipe. If you have lx/dx(cat on exhaust manifold) switch to ex style exhaust system(cat on down pipe).
I bought a XTD stage 2 clutch kit, I was told stage 2 clutch is as high as you would want to go for a daily driver, I have yet to do my engine swap though so that is not installed.
I want to get a stage 1 cam. I was told stage 1 cam is as high as you would want to go for a daily driver.
This should save you a lot of time and searching as it took me about 2-3 months of searching to learn these things!