I was able to just unbolt my delete pipe from the flange and take the u clamp off from the other side of the delete pipe. Then took the system loose from the delete pipe hanger and the next 2 hangers down system. I was then able to persuade it out. Before installing the original cat in place I would recommend grinding off the spot weld that acts as a stop on the non- flanged end, (this will give you the space to slide the cat back and forth) ,and sand the pipe good so it slides easily in the pipe. also cut back the "too" long studs on the cat about an 1 1/2". it should go in with a bit of elbow grease then. Its a good idea to have a new gasket on hand, ( I tore mine, so I need to get another one). Its funny though, like 00Turbo44 stated, the inspector didn't even look under the truck.