My DS was occasionally responsive and answered maybe three emails or phone calls out of at least a dozen over 6 months, but he sure successfully fought behind the scenes to get Model X delivered by the end of the year. Talking to the SC manager and calling Fremont helped give me assurance, even though that information wasn't always correct. One early midyear comment by the area delivery manager was, "by the end of the year". How right he was!
One problem is that the DS can push for results, but doesn't necessarily control the situation. Until the vehicle was released from Fremont, there was no clear indication of when the vehicle would be ready.
I got the call at 7 PM to pick up Model X at 8:30 the following day. Surprise! And to top it off, they provided a "all hands on deck" ceremony during delivery. Impressive.