You don't have to take off the headers to do the CAT removal.
I also have an '09 SERG and put it up on the table lift and removed just collector heat shield.
Once down to the bare header I used my plasma cutter and cut a rectangular hole in the outside of the center section of the collector area. Once the cut was made, I had to peel the piece out as it is attached to part of the CAT on the inside. Once the piece is removed, I used my air chisel to remove the rest of the converter. It cleans up pretty well. But if you're using an air chisel, be carful to not go TOO deep like I did. I ended up with a slight slit on the back side of the collector and had to run a quick bead to patch that. But if doing by hand with hammer and chisel, it can be cleaned out in about half an hour.
Once clean and the removed piece is cleaned, I held it back in place with a couple magnets to get it flush with the existing collector sheet metal. The just welded it up. The pipe is plated, but that did not matter and the weld turn out good. It has not rusted and the heat was greatly diminished, very good thing to do!
If that's all you did and left everything else as it is, I doubt that any tuner would be needed for just removing the CAT.
I did Fullsac 2" baffles and purchased the TTS Master tune from Steve. In the day, he had been dyno tuning MANY of the new '09 SERG's and offered the canned dyno proven map with the purchase of his 2" baffles and TTS. I think the whole thing was in $500 to $600 range. That's all I've done to my '09 and it's been a reach champ of a ride ever since. I was not out for WAY more power, but smoother, cooler and a little better sound. I also could expect to get around 45 to 47 mpg riding 2 up on country roads. Freeway at 70 to 80 mph drops it quite a bit.
For you being as happy as you are with your ride as it is, may be a hard sell, but the CAT removal will deepen the sound just a bit with stock mufflers and you will notice less heat on the right side. Also the passenger will thank you too. My wife could tell the difference on the back in the right foot/leg area.
If you're interested, I can hunt up some pictures I took at the time if you want to see what I did.
Thanks and good luck with your riding!