new cats on the 2001 and a straight pipe in place of the center muffler on the 2004.
the 2001 was in Detroit before i picked it up a year or two ago. the hardware holding the Y-Pipe to the exhaust manifold looks to be far too rusted to take off with out some cutting being involved. so, figured it was easier and less expensive just to weld in new cats.
and the exhaust pipe on the 2004 that comes off the back of the center muffler broke right as it exits the muffler. figured i'd cut out the center muffler and that welding in a straight pipe there would be cheap and easy.
On the 01, a new Y-pipe may be the best solution. It’s just threaded studs at the manifold that always look terrible but easy to replace if any break. And good chance the cost of individual correct cats and fab labor could be more expensive.
Looks like the y-pipe is about $450 and individual cats are $150+ each plus a few hours of labor to install.
Not sure if you had an exhaust shop quote it.
The 04 should be easy if it wouldn’t cause an inspection issue..