Can't answer the 2nd one. Houston isn't so bad that you need to drive around with a gun...well, I take that back...there are some parts but having a gun will likely just get you killed instead.
For the first one:
http://www.txdmv.gov/vehicles/drivers/new_residents.htm
Welcome to Texas, now pay us a $90 "new resident tax" per vehicle...
...Got nailed on that one with 3 vehicles when I moved here 5 years ago.