EGR and performance questions

if you remove the cats the egr wont work the way it was designed / calibrated ,the orifice on the egr is smaller with more back pressure (cats) if you ever installed a after market one they come with a orifice kit for with cat or without they are calibrated just like a carb to put the right amount of gas into it, put a 350 egr on a 454 and they don't pass emissions, that's why the newer ones (if they use one) is like a isc motor and always changing.