I wanted to get rid of the CAT's and considered getting a set of TOR's. Couldn't actually find any for less than $500 with shipping that weren't *****ed up. I also didn't want to increase the noise, so I decided to launch into a project of removing the CAT's from the stock 2013 roadster pipes.
I wasn't really sure what I would find so I took pictures in case anyone else might want to try this and/or find a better way to "skin the cat"
First, I opened up the can at the inlet end with a 1/16 ziss wheel so there would be a way to weld it back together without cosmetic issues:
So that's just the can, or outer shell. There's another pipe, much thicker, and I used a Sawzall bi-metal blade to reach through that slit and cut that pipe:
The inner canister of this thing is really surprisingly thick and is why each of these weighs 17lbs.
Before you cut all the way through, make some marks across the slit to index the two pieces so when you weld it all back together the angles are correct to fit the crossover unit.
So at this point I had no idea how deep the CAT would be or how to get it out? It isn't at all like the ceramic ones that just crumble. This stuff is really really tenacious tuff stuff. Some kind of super metal foil. All I could find on the internet was that it is referred to as a high flow catalyst?
I tried a big 3/4 inch drill bit to start but it doesn't work. It just folds over the metal at the tip of the bit and kind of makes a dent so the cutting edge can't get under the material to take a bite and bore the hole?
You can sort of see the dent it made. So I got a smaller, longer 1/4 inch bit and just had at it poking holes. Once you get a hole out of the center then you can kind of grab the material with needle nose pliers and roll it towards the open center as you would to open a sardine can.
So it turns out the catalyst material is about 4 inches diameter and 4 inches deep. It took me 5 minutes to cut open the canister and nearly 2 hours to get the catalyst out. The next one I did, I burned a hole in the center with a cutting torch and it was much quicker but still not a cake walk to unravel the metal foil.
So this is ready to go back together. You want to take a dremel tool with a stone around the inside surfaces where you will be welding so that there's less contamination in your weld. I used TIG and stainless steel rod and it welded pretty nicely. Here's a drawing of what I think is roughly the design of these mufflers:
Index marks to get it back together and aligned properly
I reached the limit for photo uploading so I will post the rest as "Skin the CAT" continued. Hope these help or inspire others to give it a try. Even if you can't weld, you can do everything up to this point and then take it to someone who can weld it very easily.