Looks like Elon has some VERY ambitious targets for TM over the next ten years that would net him $43b if everything works out.
And this is despite him pretty much stating (in the Panodaily interview) that SpaceX is where he's going to ultimately focus his time and attention
His "at least 25% margin" is actually code for 30% target, etc.
The stock options allow him to buy $15,000,000 or so worth of stock at estimated $30/share each year for the next 10 he meets his production and market price/capitalization targets.
Which are extremely ambitious!