What all are you trying to do with your EX? Do you just want a little bit of performance or do you want to have a sleeper street car? If you want a little extra performance, you can have a custom exhaust made with a universal muffler and some 2.5" piping. A muffler shop can do this for you for about $125-$225 total (depending on the muffler). Fujita has a Cold Air Intake and a Short Ram Intake I believe. You wont find a header because the exhaust manifold is integrated into the head for emissions purposes, making it impossible for a company to build a header. If I'm not mistaken, this was a problem on the 7th gen Civic's too. Other than that, lightweight wheels, a carbon fiber hood and carbon trunk (if you're getting a coupe, the same carbon hoods and trunk for the Si will work), lowering the car with springs and dampers, sway bars and anything made for the Si that doesn't have to do with the engine will work. Relocate the battery to the trunk, to shift weight around. If you don't want to do that and you can't afford a carbon hood, get a lightweight battery. These are all things that you can do to increase the performance of your car, not to mention make it look damn good
