mil illiminator ensures ur engine warning light doesn't come on, the engine light often comes on afta de-cat'n the car because of increased emissions, its just a resistor that tricks the ecu into thinking the emissions are acceptable
umm....right..on the current cat u have an 02 sensor...your going to have to take it out anyway to fit the new pipe....so while its out.....(i think this is right!)>> cut either of the cables and solder/crimp or wateva u fancy; the MIL eliminator in series with the previous cable. That should do the trick! not so sure u can use either cable though.....can't see y not....mite need verification from another member who's fitted theirs!