I have heard that the rear plate can be removed without removing the manifold, but when I did mine, I just pulled the whole thing. The TORX bolts are a nightmare to get off, as the heads will strip and you have to VISE-GRIP them off. The front plate is just a plate, and also has a gasket.
Do a search for M60 Intake Manifold for a procedure. Bill R. and Winfred have pics of what it looks like pulled apart.
EDIT: Replace the four manifold gaskets as well.