Don't take the Z-5500 the wrong way. Yes, it is powerful but you can control the bass. Good thing for that, otherwise, your walls would be thumping all the time. The sound is so clear and sharp. It's by far the best surround sound speaker set I ever bought. I believe it even rivals some home theater setups too. That good.
8ms monitors is just fine. I just got a bit excited seeing that 2ms and had to get it. You will experience no ghosting also with 8ms. It's fast.
That's a good question regarding the USB devices work before install of Windows. Try it out and see. Worse case scenario is you'll need an adapter for USB to PS/2. Your mouse or keyboard should come with one. Or you can just borrow your dad's keyboard or whoever's computer is in the house