[MESOGLEA]

I was thinking about headers, high flow cats, welding O2 bungs after the catalytics and extending the O2 sensors.
Pre-catalytics are used to reduce cold start emissions. It would take some time for the hi flow cats to warm to operating temperature since they would be located further down the exhaust path. What are the chances this set up would throw a code and/or not pass the sniff test?
Then again, the O2 sensors are between the pre and main catalytic......

 

[shinermiller]

As long as you're tuned for your setup throughout your RPM range, you should be fine....