its a lean burn engine, its designed to naturally run hot so I doubt taking out a clogged cat will cause damage but thanks for the insight.
i havent changed the diameter of the exhaust and retained a factory muffler so the mass flow and velocity will remain pretty close the tolerances set by the conservative factory tuning of the ECU and material specs of the valves and head. There is a large amount of safety factor engineered into this motor and the entire system to begin with so I am not worried.
Catalytic converters from the factory have a very low impedance on the exhaust to begin with. The VX design has the cat right at the header and when in lean burn it would toast the cat much hotter than a normal car anyway so there would be little to no flow restriction offered by a functional cat on this car.
Back pressure is normally a factor of exhaust diameter size and length as designed by the factory.
Surely you have an annual test like we do in the UK to test the car is roadworthy, which includes a very strict emissions test too?
annual safety inspection but does not include emissions anywhere past testing the gas cap to ensure a seal and the visual inspection that a catalytic converter and muffler are installed and there are no holes or breaks in the exhaust.
As far as I know California is the only state that requires "strict" emissions annual testing