I have a 2003 focus st170 and want to change the exhaust. I have a 4-1 stainless manifold and my question is can I put on a standard cat instead of a sports cat as I don't want to put on a dummy one as the 02 sensors have to go on.I will follow on after the cat with a stainless system just dont have the kind of money they r looking for a sports cat.Thanks