I would guess that a "universial" cat con sold in 2016 might have much better NOx reduction than the original cat con from 1993

I would think (hope) so too. The original cat went bye-bye right after I bought the truck. When I got this truck, it had two cats on it, the original one, then a second one back where the muffler usually goes. Then, not 6" off that cat they had a 'race' (?) muffler about the size of a shoebox, and dual tail pipes off that. The truck was loud and sounded like crap.

When I had a shop put a proper muffler and tailpipe on, they removed the original cat and installed the newer looking second cat up in place of the stock orignal. How old it was or what kind of shape it was in I have no idea. It just 'looked' better than the 22 yr old piece.

While the $650 tab still stings, the truck runs so, SO much better now, its like it lost 100K off the odometer. Hands down, the new EGR made the biggest difference, even more so than when I did the tune up.

If I had spent $650 only to have it continue to fail and /or run worse, this might've been the next step.........