Removing the cats?? Please help
 

Could someone give me some advice that knows abit more about the 05 1000rr, ive got a scorpion slip-on and was thinking about removing the cat situated by the rear sets. But im uncertain because ive read about afew people saying that you should either flash the ecu or get a PC? Is there any truth in this? I also dont want to do any unnecessary harm to the bike by it possibly running lean because of the better airflow. Im not looking for any gains in power but more for a bit louder sound. Bike is stock besides the scorpion slip on and simota air filters.
Advice would be much appreciated

If your removing the O2 sensor ,I would get a Sensor Eliminator kit to get rid of any fault codes that might come up and a PC to settle any AF issues