On mine they were both bad,the cat was completely burned out and the muffler is rusted through in places.Since i live in the rust belt no surprise.I like the way the 4.3 sounds with a standard turbo muffler not loud but no too quiet either.

 

GM 90* engines sound good with turbo mufflers on them. I have one on my 99 v6 Camaro.

 

Let's see, stainless steel exhaust system, no salt in the winters, 12+ years old, 220K miles and mine is just fine. There is a rattle do to a tweaked system that doesn't align up just right with the hangers from some long forgotten offroad adventure that is now held in place with some stainless steel wiring, but other than that?

Still plenty of miles to go, IMHO. And yes, still the stock system as I bought mine new in 2000.