It all depends. You will probably need a hand held grinder with metal cutting wheel to cut the old rusted bolts off. You may then need to drill out the cut bolts from the clamp of the catalytic converter. Then you will need to separate the rear pipe from the center pipe... joint could be rusted fast. But rear muffler may also be ready to go. In that case just cut the pipe and remove both old mufflers and install new.
Do you think you can handle that? If not find trusted mechanic.
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