Has anyone ever bunged the headers themselves in order notb to have to extend the O2 sensor wires?

 

extending the wires is so that the 02 sensors sit behind the main cat and register a working cat. If you install them in the headers you will get codes for cats- since the precats they monitor are eliminated with headers. O2 sensor simulator is the way to go, and most who done the wire extenssion still get codes and do the simulator.