So, I have been getting paranoid lately about how crazy hot the underhood temps get on the RX-7. I read that the pre-cat is prone to failure and can take the engine with it. I've got 56k on my Rex with the stock cats AFAIK. Any way to tell if/when they need replacement?

If they need to be replaced, should I go aftermarket? I'd like to keep it stock but if I can get better emissions and higher flow with aftermarket, I'll do it. Thanks for the help guys.

 

Check to see if it is still breathing....

Pull it off and check it. Go aftermarket for more reasons than I have time to mention, and put the ***** cat on when you go for inspection.

 

As laujesse2 suggested, go with an aftermarket downpipe. You should still be able to pass smog testing with one installed (although you could fail visual test).

There are many reasons to switch to a downpipe instead of getting another pre-cat, but the most important one is heat. The pre-cat generates a lot of heat under the hood.