O2 Sensor Simulator things (questions)

that would be pointless to me. it has 2" down pipes, which is what i have now. i need to actually have to re-made into at least 2 1/2" mayb a little bigger. and that wont fit anway, the crossover pipe on the 5.9 Dakota is different than the one on the Ram (i have not seen physical proof of this, but thats what im told).

anway, i think im going to just hollow out the cat and get the O2 sim. that way its there for inspection, and i dont have to piece together some sort of pipe thing to go in place of the cat.