My 92 has 180k on the original cat. While I was having the muffler & tailpipe replaced at a local shop I saw a sign on the wall that read something like this,
"The catalytic converter on your car should never go bad. If it does, something else has caused this to happen and should be fixed before replacing the converter."
I asked the guy doing my work about this and he said it was true. Let us know how things turn out.