Originally Posted by teagueAMX
As far as the ductility issue, I believe that's an issue during the forming process, but they apply heat treatment after the part is is formed - don't you agree?
I think the trade off is between strength vs lightness during a side impact and transfer of impact energy to the rest of the frame. I'm really surprised that they would be looking for weight savings on a B pillar, particularly since there's no way to laterally (side impact) strengthen it.
BMW for all apparent fanaticism, hype and marketing for e-dynamics, bio-fuel efficiency and general "green-ness" tends to build a relatively heavy sports car. Compare a e89 Z4 (a car I really like) and a Porsche Boxster or Cayman, which are about the same volume. Comparing apples to apples - DCT vs PDK - and the BMW weighs about 500 lbs US more. Compare an e85/e86 and they were pretty close. The e89 convertible top weighs about 200, so were did BMW pick up the extra 300 lbs?
Understanding the difference between Munich and Stuttgart is quite simple. Stuttgart has a considerably greater margin on their products so that they can channel this to their to manufacturing/engineering processes. And they are brilliant at it! I am 100% sure there are processes that can produce lighter and stronger alloys but BMW can't afford that with their current margin.