They put the probe into the tailpipe for testing. I'm planning on replacing the cap, rotor and wires just because they are original.
I did some research on a CAT today and called a shop that said he could cut out the old cat and install a universal in it's place. He said they sell ones with flanges already attached too.
Pelican carries this -
https://www.pelicanparts.com/catalog/SuperCat/911M/POR_911M_EXHMUF_pg1.htm
Appreciate any thoughts and help on going with a universal or the one above?