My source who has been quite reliable so far just relayed some news that will be sure to upset some people. What I was told is that Tesla will be moving to more of an inventory sales approach with Model 3. This process has already started with Model S where Tesla is getting more and more incentivised for the owner advisors each quarter to hit their goals and to push more inventory cars that are prebuilt by Tesla. This does not mean that you won't be able to custom configure your Model 3, only that doing so will take longer and prebuilt configs will generally take priority. This is also related to streamlining production and helping to increase the speed of the production ramp. We shall see if this indeed happens but I'm told this change is already happening at Tesla stores and at corporate.