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The most important thing would be to torque the intake correctly to provide even pressure and prevent leaks.
The most important thing is to clean all the oil/grease off the intake manifold and on the block where they mate. The prep work takes longer than the actual tearing into and replacing. I think it took me about 4 hrs with my brother helping. Make sure to use at leat 3/16" RTV on the front and rear of the china wall. I would suggest using "The Right Stuff". Might as well leak test the injectors before buttoning everything up.
There are a couple of write ups on the internet if you search.
Gaskets (2)
RTV for front and rear seal
seal for the bolts thread
other things?
You'll be removing stuff like AIR, EGR, and the throttle body, so you might as well pick up those gaskets, since they're pretty cheap. Honestly, Disconnecting/removing everything attached to the manifold is a much harder job than actually removing it. Be sure to label everything and take pictures as you remove, so you can put everything back like it was. It's just 12 bolts and it's off. Be sure to look up the correct torquing sequence in the FSM!