All I can say is check your Texas state law. What you might "generally" get away with and what you are going to face when that "one cop" stops you are two different things.
Generally you need tailpipe(s) that come out under the body somewhere at minimum in addition to a leak free system and muffler(s)
"Loudness" can be very subjective and I'll guarantee you it will hinge on "what you were doing" at the time.