Mark...no additions should be made to your car without your permision. If you have a reputable dealer your car will be delivered to you as configured at the price quoted. West Covina Mercedes delivered mine without any pressure other than to make and keep in contact with them. Their sales people don't work on commision because they have no supply available to work with. Make contact and relax all will be fine. If you do orphan your Smarty they will slap a bunch of dealer options on it that will jack up the price at least 5k...but hey this is America. We're going to complain about making profit?
The dealer will give you the address to ask for your deposit back if you choose to orphan...you'll get it with interest.
You haven't been a reservation holder for that long so why would you even think of walking away from the smart car now. I would be thinking of how lucky I was to be getting this far along in the process in such a short time. Good luck. I hope that price doesn't go up to much for you. Enjoy!