If the engine light is on it can be many things that are far less expensive than the catalytic converters. Have the codes checked and post the results so that someone can help you find a solution. That is if it isn't so small and inexpensive its just easier to have whoever does the diagnostic test repair it for you.
Changing the cat can help pass smog check and if it has not been done before there is a good chance that it needs replacing being 23 years old. If it is good, you won't see much if any improvement though.
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