Is there a way I can cat delete this without welding?

The inlet to the cat is very odd shaped. How can I cut the cat out and replace it without having to weld? I'd have to cut it behind the O² sensor of course, but idk how to replace the cat once cut out, so I haven't yet.

Emissions are not required in my state. I already have removed the muffler section. Wanting to straight pipe it.