A muffler can't really be "gutted". Most people assume that you mean the cat when you start saying "gutted".
As has been said above, the fine for gutting/removing a cat converter is up around 10k when you get caught. It will not improve the note or give a power gain.
Removing a muffler is relatively legal and will give your car a louder tone.
I wouldn't bother putting a "hot dog" in myself, simply removing a muffler will result in a significant boost in noise. Possibly more than you expected and long highway driving can get to be a drag with an excessively noisy exhaust.
My advice would be just got a 2.5" cat back exhaust and talk to you mechanic/specialist about whether or not to include the mufflers.
if you can its best to hear another exhaust the same as you want as each different muffler / hotdog affects the tone, ever so slightly but u can notice it. there is a massive thread in the "V6 development and modification" section on exhaust notes n setups, check that out for a heap more info :thumbsup: