You will not trip a CEL if the set of headers you buy has an O2 bung in it for the O2 sensor. I highly suggest T1R's header as it is a great unit with excellent quality! I have mine sitting in my basement for the time being, but will be installing within the next few weeks (damn winter

) Give Ben @ AJ Racing a shout and he will hook you up with one. Tell him Illusive sent you