On T&J's website, they claim their chassis stiffeners: "Dramatically increases frame rigidity". I don't believe that statement. In my context, marginal is the opposite of dramatic. Marginal and minimal refer to my accepting the fact that T&J's chassis stiffeners do add some strength, but only a small percentage of what is implied. What is a small percentage, you ask: how about 10% to 20% (my opinion). Once again, I think these stiffeners would help strengthen the front control arms mounts(my opinion again

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I count one guy in this thread who actually owns T&J chassis stiffeners and one other with home built copies. Both seem to feel they make a difference, but in defiance of your rules, no measurements are provided. Three others have plated their frames with angle iron and seem to think that makes a difference as well. Again, no measurements are provided. Richards response, as usual, is probably the most informative with some opinions on the subject and information on his own mods and the degree they reduced movement between door and body structure. Not exactly a measurement, but revealing non the less.
I chuckle every time I read that line. You're welcome to ignore theory and get sucked up into the world of the Butt Dyno. I'm willing to consider both and will continue to offer theory and my opinion. That's what forums are all about.