You wont want to use the spikes on the wood floor, because it will ruin it. They also come with rubber bumpers, which is what you'll want to use.

If your neighbors were complaining about a little mini system then it sounds like your gonna have to just keep it down because unless you completely isolate the speakers from the floor,.. like hang them or something your still gonna get vibrations transfered to the ground. And even then they would probbly be complaining.