Removing the cat will improve exhaust flow.

However the engine only needs so much exhaust flow capacity before it starts to not make any more power from increased flow. Might as well keep a cat.

Your stock cat however, probably is clogged up from being so old. You should replace it with a high flow unit. Practically speaking, it'll make just as much power as not having a cat, and you won't be spewing raw exhaust into the atmosphere.