[wiswind]

It should be a "sensor safe" sealant so that it does not give off vapors that are harmful to your oxygen sensors.
The instructions for the job indicate that you only put a dap of the sealant where the "end seals" meet the lower intake manifold gaskets.
Don't get carried away and use it all over the place.
The lower intake manifold gaskets are to be dry fitted (no sealant).
Also take care to avoid getting junk down into the intake ports......best to not clean as well vs getting the junk down into those ports to be drawn into the cylinders.

On my '96, the area around each fuel injector was a dirt/grit trap......If you flush that junk away before removal of fuel injectors, it will help prevent that from getting down into the intake.

Don't forget to clean the EGR ports while you are there.

Engine oil and Filter MUST be changed before starting the engine as you WILL get a fair amount of coolant drainage down into the oil pan.

There are pictures that show the process, step by step, in the pictures that the link in my signature takes you to.
NOTE that they are for a '96, so there will be some significant differences along the way.

If 2000 still used the "quick connect" for the 1 heater hose connection to the lower intake manifold.....it is very likely that the nylon clip unit inside it is brittle and will break.
If you buy a repair kit (a new nylon clip) before you start the job, you will be prepared for that.
There are pictures of that connector in my pictures as well.