Just wondering what the pros and cons are?
You would think gutting the cat would be the best option if it has similar results to removing it due to the exhaust laws getting tighter?
If you still have the cat in place (gutted) hopefuly this will good enough to pass your W.O.F regarding your exhaust so long as it's not to loud.
I know at this stage you do not require a cat. I don't know how much longer this law will be around for.......
I am not trying to produce massive HP just putting in place a cat back exhaust system to help the car move along a little better.