Heres a picture of the rear exhaust manifold after unbolting the catalytic converter and laying it aside. It wont come out. Just set it on the crossmember to give yourself room to extract the Y-pipe. Notice the heat shield on top of the manifold. Its held in place with the same four bolts and nuts that hold the cat underneath, which means that when you re-assemble the cat to the manifold, you have to put the four bolts up through the new gasket, the manifold and the heat shield before you put on a nut. Its a little tricky but the bolts are not evenly spaced around the cat so it can be assembled only in the proper orientation. Use anti-seize on all the bolts and nuts when you re-assemble so the next guy has an easier time of it. When you put it back together, remember to insert the Y-pipe over the crossmember before bolting up the cat. Connect the Y-pipe loosely at all connections before tightening any of them. To finish the job, replace the structural brace, re-connect the O2 Sensors, replace the splash shield and pat yourself on the back.