As long as your not blocking his driveway or parking on a painted curb you should have no problems. Streets are public property as such he can't force you to move your car. Next time have him call the cops, the likely won't show up and he himself will be facing valdalism charges for breaking your windows when he throws rocks at them.
Make sure you get his threats recorded in one way or another though or it will be difficult to prove he broke your windows or did any other acts of vandalism to you and your friend's cars.
No it isn't illegal, but most people feel that the space in front of the house is theirs first. How many parking spaces are you using at YOUR house? And your driveway?
And how loud are your friends?
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.