I have an Aplpine 9857 which will control dock style iPods. Its nearly as good as the iPod itself. I can play ANY playlist, or play by any artist, or album, or genre. The head unit is easy to install in an S2000. Run the iPod cable to the center globe box.
You can get wiring harness adpators here, and even get a kit to let the dashboard controls work on the Alpine:
http://www.gofastlab.com/s2ki/home.php