This is the article I found when I looked it up many months ago. I will post the source when I have time to research. If I am incorrect, I will admit it..........but I am not ready to give up yet.
§ 547.604. MUFFLER REQUIRED. (a) A motor vehicle shall
be equipped with a muffler in good working condition that
continually operates to prevent excessive or unusual noise.
(b) A person may not use a muffler cutout, bypass, or
similar device on a motor vehicle.
Acts 1995, 74th Leg., ch. 165, § 1, eff. Sept. 1, 1995.
Chris Harrell - 2SS RJT w/ White Stripes
HTCC Treasurer
Communications and Membership Director