Not the place to argue politics. Or climate change.

The new cat won't have any effect on performance, but may be a little quieter. And witht the engine running the way it's supposed to, the OP may see a little better mileage. Congrats on getting a smog check pass.

 

I don't know how it works in Tejas, but here in AZ, the smog check is done by a contractor. They will not give advice or speculate what's wrong with a non-compliant vehicle--not allowed.

Changing oil, magic smog elixers, getting the engine up to proper operating temp, etc. might help, but it a cat is bad or not the correct one, nothing short of a new one will get the vehicle a pass.

In large metropolitan areas like Dallas (or Tucson) allowing vehicles to spew CO and unburned hydrocarbons would soon make breathing very uncomfortable. Congrats on the pass!

 

Hey harmony good for you.
Brian, that seems like a setup for scam auto repair shops;
"What's wrong?"
"I dunno. I'll have to diagnose it."
"How much?"
"I dunno depends....."
In Ca. they have to tell you what parts of the test failed, the machine shows it on the printout and that tells you what needs fixin. Some smog shops do the work too which seems only common sense as long as the computer is showing the failed part of the test. There were problems before networking of the smog computers. The smog computer is connected to the state central database to make sure it isn't altered for any reason and to track how many bad cars are still on the street. Age doesn't matter as long as it runs right.
All smog shops will tell you to change your oil, cap rotor and plugs before a test if you have an old vehicle or if you just went in and the vehicle just barely fails. I have had a car fail then pass 2 hours later after doing the oil change and new parts. It makes a difference.