Quote Originally Posted by GAZ View Post
So the magnaflow catted x pipe has a bung for the rear o2 sensor? Is there an advantage to running with the rears on or off? Also I guess the front ones are before the x Pipes.
Yes there is a bung for the rears

The fronts are before the x prior to the cats.

The rears only give the computer info and do not affect drivabilty if turned off in the tune.

If you have a stock tune you will need to run the rears. You will also need the 02 extender harness because the catted x rear bungs are further back than the stockers and the wires will not reach.