Recently, a correspondent asked if I had any resources to help him price a BMW 1600 he was selling. I didn't have much, but I sent a few links and included my opinion at no extra charge. It got me wondering. Why are the early sport-sedan BMW's so undervalued? I mean, of course, the 1600, but also the 2002. They can be had for a song in decent shape. Excellent ones are well under $10,000, and if you want a sporty, tinker-with-it-yourself weekend car, you'd be hard-pressed to do better.