I don't know the particulars about what parameter each O2 sensor monitors, but I do know that the ECU needs inputs. Those inputs include the O2 senors and if their transmitting bad info, or info out of tolerance, it will flag a code and the engine will not run efficiently.
I hope someday a computer nerd will develop some software that will allow the Boxster the use of running with no cats (off road use only officer
). Sounds simple to me.