Further, as ModelS pointed out and DonPedro said above, Damodaran's model bases the growth in Tesla's margin (loosely, "profits") on historical data that we know to be just flat out changing on a huge level. As DonPedro said, Elon guided 25% margins by the end of Q4 this year. Damodaran's model has Tesla at *negative* .23% in 2014, increasing barely at all going forward. This to me is the other most glaring flawed assumption. Damodaran is completely ignoring Elon's guidance. Now, an analyst is free to do that with inputs, as I'm sure Damodaran would be the first to admit.
But it's irresponsible not to even explain why you think you know better than the CEO of Tesla what kind of profits they will be able to make going forward, and on what basis you disagree. Damodaran didn't do that.
So for sake of argument, change the margins by changing the "Operating Income or EBIT" field on the inputs sheet, and watch what happens.
For example, even if you assume Elon is wrong and 25% is impossible, try putting in a number that would approximate even 10%.