If the car is old enough you may be able to sneak by any state regs about HAVING to keep your catalytic converter. Seeing how yours isn't I would leave it on there and look at replacing it with a higher performance one. No use getting nailed without one and having to park your car until you get one installed again. Now to the issue of removing it for performance or sound; you will see in increase in horsepower and it will be louder but not as significant as you might think/hope. If you really want to get louder and more horsepower the only way is to put headers and bigger exhaust. 31/2" straight pipes with a catback would be my suggestion! With a higher performance cat conv.
