I know some of us want to upgrade our model S to AWD, and Tesla is doing a trade-in program but I'm sure we are not going to get a lot, especially those who put a lot of mileage on their car. My question is can Tesla retrofit the older car so that it can be upgrade to AWD? by doing this, we could save the hassle of trade-in our car or having to sell our old car and buy a new Model S AWD.