Thanks EB. That makes sense and is what I thought, just checking and hoping that perhaps I didn't need to replace my cat in order to realize some gains from a freer flowing exhaust and larger pipes.

Aside from the late model intake upgrade (1994 intake on a 1988 22RE) my motor is stock, so I think I will just put a Dynomax Super turbo muffler on with 2" pipe between cat and muffler, then 2 1/4 from muffler back, as per your recommendations.

My understanding is that this should give some moderate power gains as well, but perhaps not as much as re-doing the entire system.