I bought a Alston Avenger chromemoly kit car chassis that a local guy had assembled and welded up years ago. it look nice but he had mistakenly used .065 wall tubes in the left front door upright bar from the foot bar and used the same material for the foot bar that ran across the front behind the motor. The SFI spec called for .083 tubing there so it wouldn't certified for racing
Make sure and sonic test every bar along with the SFI spec. sheet in your hands when you do the testing