The codes don't really mean that the sensor is bad and should normally always read correctly with a scanner and show no signs of bad mpg or sluggish performance.
They are just saying that the computer is not seeing the correct amount of switches lean and rich of stoich (450-550mv) in a given amount of time. Say it needs to see 90 switches in the 60 second test but only saw 80, it then sets the code are 2 failed times. It's a pretty common problem with header installs because the o2 sensor placement is now different but I haven't seen much of this problem on stock exhaust.
I only use AC delco/denso sensors too, I feel that bosch sensor end up giving people problems.
