The thing being is I don’t understand why they messed with it in the first place. Any good tuner can make more power without altering the emissions. Modifying emissions is like taking a short-cut. In no way am I dissing BCB, they just should’ve taken a smarter approach.
Unleashed, GH, BK, and 5* are all strongly against modifying the emissions. GH is probably the most strict. Heck it’s all over their website.
There’s more to emissions than just modifying O2 sensors. In the calibration, there are many tables that all have a job on reducing emissions during power production, cruising, cold start, idling, etc. Anything from fueling, spark, airflow, exhaust, VVT, etc. The list goes on.