I just installed OBX headers in my 2005 honda civic dx and it wasn't pleasant. First, I had to stretch my O2 sensor that fits on top all the way to the right of the header needless to say that I had to cover it from being melted. Second, just when I think things are going right, I turn on the A/C and the car vibrates like mad while idling (nothing unusual I suppose). Finally, to make things worse, the darn "check engine" light comes on! Will somebody please help me ASAP! Thanks.

 

Well seeing as how the LX has an integrated cat in the header, you are now running without a cat, thus the check engine light. You should be able to find an o2 simulator to fix this.