I've sent a total of two e-mails to my DS, the first one he responded quickly which was the introduction e-mail and I replied to ask some questions about the earliest date to apply for financing.
The second e-mail, I asked about potentially moving the delivery date as I won't be available during the two weeks that the car is supposed to be here, I just wanted to make sure it wouldn't be a problem to push the delivery date a couple weeks. That e-mail went unanswered for 3 days. I called him and left a VM, another day went by and nothing. I called the main 1-800 number and they just told me I'd have to talk to my DS about it.
I e-mailed again saying I was following up on the question, this time I CC'd everyone that was part of the intro email that was sent to me. After a few hours one of the people I CC'd replied saying it won't be a problem and they'll just hold the car at the service center for a couple more weeks until I'm available to pick it up, however I never heard back from my actual DS.
I'm happy with the overall experience so far. Being able to select everything online and actually order the car is a big improvement over the regular car buying experience, my DS hasn't really added anything to that experience tho, if anything it's been the only bad part about it.