2006 Charger R/T 91 octane cai tune

[CountWilhelm]

I am about to add a Corsa Xtreme cat-back system...do I need to run the 91 tune post-installation/or set the stock tune then add the system then re-flash the 91 tune/ or do nothing...I don't know anything about O2 sensors other than they gauge/control fuel mixture in some manner...have been reading about turning the rear sensors off...what happens when this happens? how does it affect the tune? I have added a fast learning curve tune to my hypothalamus and it seems to be working but the more technical jargon croms me out so please use terms an old as dirt layman can understand!! Thanks, I greatly appreciate all responses I have had on this forum!!