Hey, I'm late to the party.
Matthew, from your original post -and I want to be clear -the driver sounds like a nasty piece of work to me, and certainly shouldn't have reacted that way. However, like life, some things aren't clear cut (and this isn't to say you acted incorrectly or that you're wrong). I think when you make comments that may aggravate a situation -and I certainly consider what you said certainly wasn't bad but could cause a response as evidenced by what happened -you can get bad experiences.
Again, what you said shouldn't cause such a reaction in a reasonable person, but clearly the person wasn't reasonable. One way to avoid such situations is, to put no finer word on it, bite your tongue. For example, if I see Mike Tyson in the street, I could easily go up to him and tell him he's a no good ear biting cheat who beats women -note I could (and I would arguably be correct). Would I? Heck no! While there's no law against doing that, and Mike Tyson shouldn't beat me to a pulp for simply expressing my opinion, I think clearly it's a very, very bad idea. Maybe imagine every driver is Mike Tyson? After all, who knows who a driver is and their mental state anyway?
Having said that, clearly there are times where someone's actions elicit a strong Anglo-Saxon invective and a less than gracious description of what they are doing if they put you in danger. I'd be surprized if there's anyone on this board who hasn't done that at some time or another, and I think it's very understandable. But from your description, it sounds like this isn't the case -again, I'm not excusing the behaviour of the driver, but sometimes it's easier to not give reason for a confrontation -you can't assume everyone around you is reasonable. You're now at the stage where you are considering dealing with the police and possibly other time consuming issues, let alone the possibility of dealing with this unreasonable person again.
Again, I want to state clearly what you did was not wrong to a reasonable person, but you have to be prepared for the consequences from unreasonable people. It's your choice.