Go for White. It and Plum Crazy are the only acceptable colors for Challengers. What? Plum Crazy isn't an option? Then you have only one choice.
Definitely get the spare. Apparently, it's easy to get the donut from the factory, and as has been noted, it fits under the trunk mat. Believe me, a full-size spare takes up too much room in the trunk. Hence, I went ahead and ordered the donut spare, too, and now am waiting and waiting and waiting for it to arrive.
Have fun with your car, even if for some odd reason you don't get a White one!