Hawkson, you should really search more on these forums before asking questions.
The break-in issue has been
covered extensively many times.
So starting from question 3 downward:
3) The receiver typically has safety protection to control for high heat and high loads. It will shut itself down under these conditions.
4) Your sub will not bottom out.
5) Do not pour liquids on your reciever and it will be fine.
6) What exactly are you trying to listen for that you need the LOTR dvds? High notes? Sub notes? A good sub note is in LOTR 1 in Balin's Tomb when the goblin drums begin.
7) Reference varies depending on who you talk to. I believe the value you are referring to is 75dB. I've personally not found it to be critical when equalizing the system.
8) You can leave the system on all day if you like to burn electricity for no reason and help push forward the demise of our degrading electrical grid and the consumption of limited, non-renewable resources.