Items included in the FedEx packet from Tesla:
MCO (Manufacturer's Certificate of Origin)
Bill of Sale
Application for Registration which signed by Tesla (called Application for Texas Vehicle Title, form VTR 130-U)
Items to bring with you:
checkbook to cover any expenses (tax plus fees)
proof of insurance (might not have to be the Model S but any car you currently have registered)
copy of final MVPA that has taxable amount and tax + registration fees owed
If you are transferring vanity plates from old car to Model S, drive old car to DMV and then bring both plates (physically take plates off of car) into DMV. They'll transfer them to your new car and issue new registration stickers for old and new car. Also, they can reissue new generic TX plates for old car.
Note: I'm trying to double check to make sure this is all accurate. If you see any corrections needed, please post below. Thanks.
Thanks for TXjak, Lynn005 and Sublimaze1 for updating this information