Did a quick look at BWM dealers in your area an found this for an example. The 335is was a late model add that fell between the 335i and M3. Harder to find since production was more limited but seems deprecitaion has put them about the same as a loaded 335i (and 335is are almost all loaded by default). Big difference include the dual clutch transmission out of the M3 (DCT has instant shifts and feels more like a manual except for the clutch/shifting part). Also has some extra power, exhaust sound and body kit.
http://www.tombushbmw.com/certified/...e784484667.htm
Some info:
http://www.autoblog.com/2010/01/28/f...-a-special-on/