97-01 Catalytic Converters prone to failure too?

My 93 XJ had the good ol' rattling cat back in the day, so I replaced it when I did the muffler. I now have a 99 XJ w/95K miles with a rusted out muffler which I will be replacing soon. My cat is not rattling even if I whack it with a mallet...so I think it is prolly still good. It does have quite a bit of exterior rust though. Are the 97+ cats prone to failure like the old ones were? It is a different design (round instead of oval), so maybe the issue was resolved? Just wondering if I should go ahead and do it when I do the muffler.

Thanks.

My 98 has 140k on the original cat and it still passes Cali smog testing. But rust isn't a factor on this one.

I have a 98 that has rusted fairly bad on the outside, but I haven't noticed any problems (i.e. clogged) and I have 168k. I might go wack it later on to see if it makes any sounds.

190K+ with no problems. I found a crack in the header and the clamp to the muffler has disentergrated... I think i am going to replace the whole thing soon including the cat just to get it done once and done right. I hate working on exhaust systems....

Supposedly when the manifold cracks it allows air to enter the system then passing the O2 sensor and telling its lean, the comp then richens the mixture a little and the cat gets overheated burning the xtra fuel.