I thought this was really interesting...
2012 Tesla Model S Electric Sedan: Industry Analyst Weighs In
(4) What can we learn?
The 2012 Tesla Model S is one of the most vertically integrated cars I've ever seen. I wasn't aware how much of the technology in the Model S was developed in-house.
Tesla makes nearly everything on the Model S itself. The exceptions are some of the trickier bits, like the pedal box and steering column, which it gets from Daimler. Tesla even makes its own molded plastic parts, using machinery left by Toyota at the Fremont, California, assembly plant.
I suspect some of that self-reliance stems from finding the existing base of automotive parts suppliers uninterested--or unwilling to work with Tesla for anything other than exorbitant fees. That may have forced Tesla to go it alone.
On the plus side, that means Tesla can make very rapid design changes. On the minus side, it means the company's costs are not terribly negotiable, as there isn't competition among suppliers for the needed components. In other words, the fixed cost of Component Z is whatever price Tesla itself can bring it to fruition for.
2012 Tesla Model S Electric Sedan: Industry Analyst Weighs In