Friend of mine is a diesel tehc at the local dealership...he was telling em he found out the Ford trucks manufactured in Mexico that are not for eport to the good ole US of A don't have the EGR coolers, DPF's or any other emission junk and they are not having any problems what so ever. SO...My opinion is to get rid of all the emission crap (cat, EGR cooler DPF, etc etc) and drive it like you stole it.
but will I ever get another state inspection passed
If you are worried about inspections, gut the cat and put the case back on...I have never seen anyone drop the exhaust to see if the cat is actually operational, and they don't hook them up to the emission machines ( here anyway). Good lcuk with the truck, hate to hear about the probs.