I haven't came across any real answer. I am looking to replacing my oe cat converter with a high flow. Will this have a change in my air and fuel or how the car may perform after the motor already has been tuned? It is a b20vtec on pump gas. I know gasoline is not as sensitive as e85 but I just need a second opinion before I actually replace it and then come across a possible "cel" and all.

 

I'll put it this way. I got my H22a tuned with a stock size header. Replaced that header with a long-tube 4-1 drag replica header, totally different design. Engine runs fine and no CEL. You'll be fine