There are no emissions tests here but I would never even consider running without a catalytic converter.

Besides the obvious poisoning of the environment for a minimal amount of power, your car will sound and smell absolutely awful. Not only that, but regardless of having or not having emissions testing in your area, it is a federal crime to tamper with or remove the catalytic converter. If you are caught, you could potentially face several thousand dollars in fines.

I am just using a generic 2.5" Magnaflow high flow cat that I bought off kteller (I wouldn't recommend buying from them, though ) for ~$100 and had a muffler shop weld on some flanges to work with my downpipe/exhaust setup. You will also need to have O2 bungs welded in if you need them.