Hate to break it to ya guys, but it doesnt matter what material your case saver is made of, it wont save your case. They all flex and they all will put pressure on the cases when they do flex. LoL. Been there done that. Tm design works... Broke case. Dg billet....broke case, no-name poly unit off egay.... Broke case.
They help reduce the chances of breaking your cases so bad you have to replace them, but none of them will totally prevent a broken case.
Luck is about the only thing going for ya. Haha!
Spend the money on good sprockets and chains and keep your chain lubed and adjusted properly.
Jared