If you are legal to the requirements and statutes of the state where your car is registered, then other states must honor it, so if your tint is legal in TX, NY courts can not convict you if you are visiting. But, that does not mean a cop won't give you a ticket and require you to present your defense in court. It would be an easy win, but you would still have to show up or hire a lawyer to represent you in absentee, though most prosecutors would throw out the charge with a quick phone call to their office. The flip side is most cops are not going to bother writing an out of state car on a charge like this, unless you do something to piss them off, like parking in two spaces at the same time or having a "F@#* da Police!" bumper sticker.
