Catalytic converter bad??? What are symptoms? How do I replace it?

Hit a big, big bump. Car hopped.
Now hear a low clucking sound out of exhaust.
At cold start get a sulfur rotten eggs smell from exhaust.
Is this a catalytic converter problem.

Has anyone replaced their catalytic converter?
How did you do it ?
Any tricks/tips ?

Please, wrench turners preferred.
Looking for better advice than "Take it to the shop".

Thanks

Pretty strait forward - 13mm wrench and 12mm wrench- looking at about 1000 bucks for a factory one. Most after market are junk and will throw a code for the cats in a couple hundred miles.