You think this was a crime of passion? Or extreme negligence? Those are pretty much your only choices. Under the law, the very act of using a firearm is automatically use of deadly force. Even the mere display of a firearm is considered use of deadly force. This is why police officers are justified in shooting an armed suspect even though he may not have fired at them first.
There need be no specific period of time for premeditation to exist. It is sufficient that the egging had already occurred and the shooting was a response framed in the form of a punishment and that indeed is premeditated murder.
But perhaps I'm splitting hairs. After all THIS is a primo example of why lawyers make obscene amounts of moola! I know one thing, if this shooter got off on murder 1 in a criminal trial, he'd get screwed to the wall in the inevitable wrongful death lawsuit where the level of proof required to assign liability is significantly lower than the criminal court! Just ask OJ.
How was this any other than? It wasn't like this guy was driving around after midnight thinking, "Dang. I hope some kid eggs my ride so I can cap his a$$..."
Until they find the shooter, we really won't know what motivated him. Judging from the time of night, it very well could have been alcohol related as well. I don't know, nor will I hazzard much more of a guess than I already have.