wHAT IS THE BEST WAY TO BREAK OUT THE MATERIAL THAT IS INSIDE THE CAT?

You can use a pipe cutter - there's a post online here somewhere with pictures of a guy tearing his open. His was from Mack tools and had a chain on the end of a bar. Sorry I can't give you the URL.

I tried it on mine with little success, I was expecting it to be more brittle material like the older ones, but I found it to be rather soft. and now, well lets just say my CAT looks strikingly like a piece of 3" pipe ;)

Not that I'd condone an illegal activity, but I read once somewhere that a piece of 3" pipe thru the center of a Cat shell looks like a normal cat and flows better; if I recall correctly. For my own purposes since I'm a K1500 4x4 I have a special bypass pipe I swap over to when I offroad, it is comprised of the old turbo down pipe flange welded to a piece of 3" JC Whitney 304 stainless flex pipe and wrap around clamped to where the Cat outlet normally goes. I knocked out the studs and replaced with common nuts & bolts.


When I'm finished offroading I reinstall the cat same method as the offroad pipe, that way I'm legal if ever stopped & inspected, ever so often I might forget to swap back over I usually remember to confirm I put it back on before going to inspection or dealer for service that wants to argue about "performance modifications" voiding an extended warranty.

I had to sawzall the trap just to get it off the truck.
The cross members don't give you much room to drop it.
If I had to have it back, I would want at least a 4" trap or one off a big truck.

Kitty recipe: Need drill, hammer, and pry bar. Combine ingredients with your own imgination. Prep time: about 45 minutes to an hour.

I first used a long concrete drill bit. Oh yeah, don't forget the mask...that dust will kill you quicker than you can say, "Is the cat back?" After that, it was fairly easy to drive the pieces out with a small diameter steel pipe and hammer. I then cut a 4" hole on either end of the Cat, passed the new 4" straight pipe thru the hollowed Cat and welded the Cat housing to the new straight pipe.

I didn't think about doing something practicle like running the new pipe thruogh the old CAT.
nice CYA approach.