Quote Originally Posted by green91 View Post
Its actually a felony to modify any emissions control equipment for on-road usage if you want to get legalistic. There is also a visual inspection so if you have a test pipe bolted in or even a straight pipe welded in, its automatic failure.
Correct as is a plethora of other car modifications including HID's, different spec bumpers, performance engine parts, lights, lowering the car even an inch.

In which case - Just knock out the internals and you pass visual inspection! But if your getting an inspection at all you better have a Cat on as will not pass anways!

Quote Originally Posted by green91 View Post
Post cat o2 aren't used for fuel trim calculation in ECU on obd2 cars.
There are always exceptions, but again you are correct!