when getting one from the store get one for a 2002. the newer style gaskets are better than the paper ones from the earlier ones.
when taking off the one pulley on the driver side to get to the bolt behind it...keep it in the exact same position when you lay it down with the bolt still through it. it matters which way it goes back on.
the waterpump hoses by the thermostat suck...make sure you have a good sized channel lock wrench.
if it wont come off the block after unbolting it...grab something big and smack the the bell on the wp. itll fall off.
get a can of gasket eater if you have paper gaskets on there stock....they suck to scrape off and it will make things a bit easier....wire brush or razor works well...shove a rag or something in the holes of the block so you dont get crap in it.
make sure you run the car for a few minutes checking the antifreeze to bleed all bubbles out.
taking the throttle body off makes life easier too.
use small dabs of super glue to glue the gaskets to the block before lining up the water pump...makes life easier when lining it up.
it doesnt need to be super tight just give em a good oooomph
rtv sealant is a pretty broad term...if anything permatex makes a water pump and thermostat housing sealant for added protection...i didnt use any sealant when i did the pump in my z28 last year. the composite gaskets are pretty easy to work with