When you take it to get an ODB-II check, those o2 sensors that are turned off will show "not ready" and that'll fail the test. They have to be turned on in order to pass, but the problem is the CEL that comes on. I asked AmericanMuscle about this and they said the highflow cats are a hit or miss in this situation. I have to get a ODB-II check soon so hopefully they'll take some dough to let me pass.
I am in the same boat as you sir. It really is a hit or miss thing, just depends on how good of a work-day the inspector is having and if you are lucky! Worst case scenario we will have to just trial and error a few places. Lol.