No one has brought up sales tax yet. If you’re buying from a dealer they are going to charge you TX sales tax. Then when you get to NY you have to pay NY sales tax when you register it. Texas sales tax is 6.25% + any local county/city sales tax. Then you get here to good old Erie County and have to pay 8.75% when you register it.
And guess what, TX is on the list of “no sales tax credit allowed” states:
http://www.nydmv.state.ny.us/forms/dtf804.pdf
Now, there is a little “*” there, about requesting a refund from the other state once you pay NY’s sales tax. I’m guessing that can be anywhere from super easy to damn near impossible depending on the state.
When I bought my truck out of state it was from MI, a state where you can get full credit for the sales tax paid when you come back to NY. So I paid 5% sales tax in MI, and when I registered it in NY I only had to pay 3.75% (MI 5% subtracted from NY 8.75%).
Also, not all states offer transit permits to private citizens. Make sure Texas does before you get down there and realize you have no way of getting the car home. They will require that the car be insured. I talked to my agent first and we agreed that if I decided to buy the truck when I got there he would add it to my policy and fax me the temp insurance tag. But that meant I had to go on a Friday since his office isn’t open Sat/Sun. All things to think about.