Just a note to anyone removing the OEM cat back for any reason :
invest $20 and get a new set of hanger donuts :
Crossfire Muffler Hangers
Cut the old ones to remove the muffler, it's not worth the hassle to try and remove them without destroying them ( or your hand/arm ).
Also, remove the big black baby buggy bumper thingey from the OEM and re-use it above the OBX as seen at the top of this picture :