Don't take out your catalytic converter. It has a huge purpose on your exhaust. "A catalytic converter is an emission-control product that cleans up a gasoline-powered engine's exhaust. Exhaust gases leave the engine and pass through one or more catalytic converters where unburned hydrocarbons and other byproducts of the combustion process are converted into less harmful emissions." quoted from
Honda catalytic converter
that's the main reason why you should keep your cat.