Congrats, Mark! Glad to hear you're up and running.
A 1000 watt Sony system will be enough. Does it have a sub?
And remember, it does
have a volume control! One consideration is that you'd probably have the option of choosing different pre-set sound fields, if you need to. Something that's not surround (again, if you need to) and will fill your viewing area with nice even (but not so loud) audio, for those nights when you need to keep the volume low. So you can concentrate it, and make it easier to hear at lower levels.
And you never know, the neighbors might be movie/drive-in fans and this could end up offering some common ground. That may be a stretch, but it could happen. I would attempt an invitation but you know your situation better than any of us here.
Have fun and good luck!! Post some pics when you can.