I (as well as a few others on the forums) have in the past made comments that we suspected Tesla was using an Agile methodology to build the software in the Model S. This slide from a TEDx talk given by Jeff Sutherland seems to confirm this. Even more surprisingly, Dr. Sutherland makes a comment that someone is working on building a car using the Scrum methodology. He doesn't specifically say it is Tesla, but I wonder if that is who he is referring to.