"Buy what you like" is my motto. There's no such thing as a "great deal" on a vehicle you don't like. The OP brings out a good point that 99.1% of people who buy high performance cars like the M3 rarely make use of it.
However, there's something to be said about a car that's actually "built" for aggressive driving. BMWs are renown for having the ideal compromise between performance and practicality. While we don't make a habit (usually
) of sprinting down the street or around the corner @ 100 mph, it doesn't take such maneuvers to appreciate a high performance car.
Like for example, my new car, a 2007 Nissan Maxima, the "four door sports car" (right). As you quite imagine, the difference is day and night between this car and its predecessor, a '96 Buick Regal. Once again, 'steering feel' is regained. The tires don't howl if I take a corner faster than 20 mph, and the brakes have bite. It makes the car a lot more fun to drive, but also it feels safer--no more feeling of turning the wheel and feeling like the car would continue going straight ahead.
I have no doubts that if I owned BMW, it would be night and day compared to the Maxima, but so is the cost. All said, there are some good reasons to buy a high-performance cars despite not taking them to the track for a drag race or autocross.