If you've reset your ECU, it takes a while for it to complete the catalyst testing, and then the light will come on with a catalyst effiency code. *shrug*
Watch out for detonation! I can't stress this enough!
Looks nice with the black Jet-Hot coating, though. Makes the engine bay look stock. I wouldn't remove it though... it keeps out the heat soak from the engine bay more then letting the cool air cool it down from the scoop being open.