From your first picture it is a prime example of improper installation.The piller bar is layed back way too far and is attached at the side of the halow bar.It should be attached at the underside of the halow to give any support.Many times an installer will try and follow the windshield and body contours which make the angles less effective for support.NASCAR uses MS cages for impact absorption(give)CM is lighter and harder and has little impact absorption quality.CM is more prone to break rather than bend.And because of it's hardness it will fatigue from twisting and loading in time.This is why prostock,top fuel and other classes constantly update their chassis.If you have ever seen a CM Chassis wrecked you will commonly see tubing breaking not at the welds but in the tube body.And also a good oxy/ecty welder can weld CM just as good as a good tig welder.A furthur note,with all the approved and new welding techniques CM can be mig welded to perfection,NHRA just doesn't allow it.They fear that that fitment would be compromised buy the ease of application of mig welding,where as you can't very well hide gaps with the tig process.Structural design, effectivness,fitment,weld and application are all important part of how you choose material and build a cage or chassis.