I did my '09 SERG a bit differently. First off though I bought 2" Fullsac baffles and the TTS Mastertune with their dyno proven map. Believe me, they did lots of the '09s when they first hit the streets and I've not had any issues with the tune or performance of my SERG.
Back to the CAT.
I put my bike up on my table lift and pulled off the heat shield to reveal the collector area. I then took my plasma cutter and cut a rectangular hole in the side of the collector that was slightly longer than the CAT. Once I peeled out the tin, which was still connected to the CAT, I used my air chisel to hammer out the rest of the CAT and smooth things out. After that I MIG welded the plate back in the collector and installed the heat shield. This was all done with the header pipe still installed on the bike. This whole process took me about an hour of fiddling and was not hard at all. But..... the CAT is very hard and does not just fall out. It has to be chiseled out.
It really did reduce the heat and the sound was just a "bit" louder, not really noticeable if you didn't know it was out.
Cutting the pipe in half and digging out the CAT requires a complete removal from the bike. Of course a new Fullsac X pipe does too.
If someone only had a MIG welder, you could cut the rectangular plate out with a cutoff wheel. Just about the same either way.