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You should probably just order now and just tell them when you want your appointment. I don't think they have any problem holding the car for a couple weeks since they already have your 2500$. Also, someone might buy it in the meantime.
I put my deposit down on 12/11 and they wanted me to pickup late this week, but I pushed them off to 12/18 since I have to drive 2 hours to San Diego for pickup.