2000 Z71 i have four 02 sensors 2 before the cat & 2 after the cat..i would like to remove my cats and replace with pipe , im already running true duals with flowmasters super 44's.. my question is what will i need to do to the 02 sensors?? second question if i just cut off the cat after the 1st 02 & before the 2nd 02 it should be fine right?