I went ahead and replaced my catalytic converter today. A few months ago my Armada threw a SES light code P0430(bank 2 catalytic efficiency below threshold). I tossed some Cataclean and Seafoam at it and the light went out after a few miles. A little over a month later, the SES light came back on code P0430. I ordered a premium manifold/catalytic converter from rockauto.com part number 40638 which arrived in no time. It took about 4 hours from start to finish. The factory manifold was indeed cracked in the area where they all crack.