What are the steps to replace the driveshaft flex joint in my car.

Unplug the secondary O2s, drop the exhaust from the header back remove the heat shield and unbolt the driveshaft from the trans and unbolt the center bearing. Hang the driveshaft with a bungee and unbolt the flex joint from the trans. The flex joint has arrows to mark its orientation. Spend the extra money and get an OE flex joint from the dealer. You don't want to do this job twice. Also pick up new copper nuts and flanges for the exhaust to header connection. If you have an excessive amount of rust on the studs connecting the header to the exhaust center section you may have to replace them. They will have to be heated and pressed out. You can get new studs from the dealer as well. Avoid using a hammer on the studs as you can damage your primary O2s if you don't remove those from the impacts and vibration. If you have a lot of rust you'll need a torch to avoid snapping old hardware.