I'll add gutting or removing a cat will do absolutely nothing for power either....unless yours is plugged. Ive tested that one on more than a few vehicles even bench flow testing them seeing 2-3 times the flow capacity and still Nada in the way of performance gains on the vehicles.
Not running a cat on either the 2.5 or 4.0 is a step backwards. These engines are definitely designed with needing some backpressure in the exhaust. I have had to gut the cat on my 2.5 in the past waiting for a replacement and it was not happy at all.