i would recommend putting the sensor BEFORE the CAt. I was told this buy a fellow SCT tech. and a AEM tech. reason is, installing after the cat will cause the reading to flux. you won't get a accurate reading. the flow of flume builds up in the cat and release a reading only a wack job can read.
when i had mine in my second o2, i had reading from 11 to 14..... and it should of really been around 11 to 12, 13 is getting close and 14 is past....
just my cent... but what do i know?
my focus is for sale....