I failed my subframe with the SCA 21mm bar (which incidentally has the same stiffness as BAT's 22m bar, but that's another discussion).
First the 'tab' end of the bracket (not the bolt/weldnut end) began to bend. So I had that welded up with Aussie backing plates so I could use 2 bolt brackets. Then the welds failed. I was just rounding a mild corner when I heard a loud creak and then a thunk as the bar separated from the subframe.
Bottom line, the stock subframe was highly optimized for the stock bar. Any other bar will eventually lead to failure.
