1999 Tiburon with 113,000 miles and I needed to replace the cat. I was running rich for awhile but got it fixed and it must have clogged up the cat some because it was pretty bad. The good thing is I was able to get a performance high flow one for it and now the car is good as new with some hp gain.

 

My 2001 Tib cat died at about 160k miles. It had gotten so clogged that the car wouldn't run past 2000 rpm and couldn't go over ~30 mph. When I pulled it off it was almost completely melted and clogged airflow. I'm surprised the engine even ran. Put a new one on and a year later still doing great!