[dsraven]

intake is easy but remember to have an inch pound torque qrench on hand to do the intake bolts after. check the intake for cracks as well, especially if the engine came from a wreck. under the intake there may also be the knock sensors, depending on the year of engine, and they are prone to rusting due to a bad seal on the wiring grommet and the sensors being down in a deep well. there is also a youtube on fixing that which will include a new short harness with grommets attached and a better way to build a silicone dam around the area so water runs off around the grommet instead of right over it.
when the intake is off it would be a great time to clean the throttle body as well. before the intake comes off would be a great time to flush the injectors. ensure the engine nice and clean prior to dissassembly so nothing falls into an intake port. with the intake off and upside down you could use some carb cleaner and a nylon brush on the injectors to clean the outside area. I usually stuff some rags down the intake ports as soon as the manifold is off so nothing falls down there.
here are a few pics of what you will be getting into. notice how clean the intake and injectors are. this is on my old 03 avalanche. i run seafoam in the tank after every oil change. the intake runners are like new and the injectors are really clean as well. highly recommend the stuff.