This excellent post on the Surly Blog tells how it should be done (except for how you get to track down the motorist through their license number. That takes a level of cooperation from law enforcement usually beyond ordinary mortals.)
One time long ago I pulled off a similar coup in Annapolis. I had an ugly encounter with a bright red Camaro/Firebird driven by a midshipman. I could tell by his vanity plate that he attended the Naval Academy and expected to graduate in 1985. Everything else about his personality I got from the way he drove.
We exchanged "passing honors" and went our separate ways. I went home and typed out a letter criticizing his conduct as unbecoming an officer and a gentleman. The next day I cruised the Academy looking for his car. Many mids had covers on their cars, but the silhouette of the General Motors cockroach is unmistakable, whether the Chevy or Pontiac version. I lifted skirts on every covered Camarobird until I found the right one, and left my letter tucked safely out of the weather.
Sadly I never got the follow-up that Swervy got, but I know I let the arrogant motorist know that I could find him and his conspicuous vehicle pretty easily.
People think twice when they fear repercussions. It's the right answer for the wrong reason, behaving nicely only because you fear punishment, but I'll settle for that if it gets me some peace and elbow room on the road.