Gun rights and ‘self defense’ rights in TX are incredibly vague so they’ll nail you. Just how it is, even if you can already legally carry in your car. They’ll screw you.
That depends on what part of Texas. I’ve had a shooting incident in Dallas and it wasn’t too bad. The many hours in the police station being interrogated weren’t a lot of fun, though. (I didn’t have a specific lawyer I could call at that time. I do now.)