3g hemi gas mileage
It was my understanding that only California cars used four O2 sensors, two before the Cat and two After.
I BELIEVE if you use the factory service tool you can turn off the two sensors after the catalytic converter.
Also If you are looking to find someone to ship a catalytic converter to you in California (I had to order one for a 79 Chevy PU, and couldn't get anyone to ship one to me for a while) Try Amazon, they had EO (executive order) Cats that are California legal. Plus they were pretty competitive on price.
Regards,
Joe Dokes