Last month I traded in my 2015 AP1 Model-S. I let Tesla take it so i could get the maximum value for it - and this required a locked in order. I'm also one of those people thats attempting to get as late of a build as possible, next year. All said, my wife and i talked it over and thought since we've had (2) Model S (also had a 2013 P85) already and with expanding family factored in, perhaps it was time to move to Model X. My Salesperson said they needed to investigate, but its been a long time waiting for an answer on whether or not its a go. From what was most recently explained - apparently the trade in was the sticking point - says it was tied to a VIN and there could be DMV penalties. From what i am reading the VIN could change anyway with 2016 -> 2017 builds. They also claim to not have come across this, someone changing models on their order. Wanted to know if anyone else out there has any similar experiences. TIA.