I decided not to wait. The concern is that you may not get delivery before the end of June, thus risking the $1875 federal tax credit. Right now there is almost no inventory- and all the people placing orders now will be ahead of your MIL in line. There are many people who have been waiting over a month, so even if she placed an order today, there is no certainty that she'd take delivery prior to July 1. Considering there doesn't seem to be a demand issue, and the only certainty is that you'll lose $1875 by taking delivery on July 1, I just don't see the benefit. Plus, why not order now, and if Elon comes out with some amazing incentive of June 15, you just cancel your order and re-order to get the incentive.