This is off a Saturn, General Motors, had a P0420 catalytic converter efficiency and the car was losing power, as you can see how the guts start to break up and block it, One side is broken up and the other side still looks good. 

Sometimes these oxygen sensors can be pretty rusted and unable to remove, at that point it’s better to just install a new sensor bung

Some of the popular mufflers that we sell, FlowMaster, magna flow, classic chambered power sticks, race bullets, etc.

No Muffler, straight pipe! Sounded good!

Listen to it here .

We installed a Powerstick and dual tailpipes. Sounded Really Good and Agressive!

Check it out

http://youtu.be/pJGRnjFC_K0

Here is a nice Camaro SS. We removed the rear mufflers. I think this is the best thing to do to these Camaros for sound and performance. Here’s some clips.
Part 1 is the original. Part 2 is after it was finished, and part 3 is a sound clip.

They all sound good! 

http://www.youtube.com/watch?v=hLZUYh7uN5U

http://www.youtube.com/watch?v=3IDCgSw98cM

http://www.youtube.com/watch?v=xTglhKjlYzQ