Congrats on the 500 purchase. The fun thing about these subs is that you don't have to worry about hurting them while learning their limits. So go on, you know you want to, turn the vol up on the sub to the 11 o'clock position... see if you can tell the difference.
I know what you mean about things rattling in the upstairs. I have my HT in the basement of my two story house. It shakes things in the walls on the second floor!
"Never, never, never give up "... Winston Churchill