I got the 4cyl ulev vtec in my 2k accord coupe. I'm considering buying an intake and possibly doing the illegal hi-flo cat and nice exhaust system. By doing these mods will it mess with the engine causing problems because its an "ultra low emission vehicle"??? also,I would like to do away with the pcv connection between the valve cover and the intake and just stick a breather filter on the valve cover. technically the engine will still breath it just won't be recirculating through the engine as if it were hooked to the intake. has anyone else done this???

 

or you could just not do all this wasteful **** to your car. It will cost more money than it's worth and you won't get a huge HP gain. Try not to kill the environment to...
Don't take the cheap way out of things..
You can make your car faster in less destructive ways to the environment.
If you want a faster car, buy a new one, or spend the money and turbo it.
If you like the pretty sound of a new exhaust do it, but aside from that, you won't get anything else.