I have the SCA 21mm bar and needed subframe reinforcement.
Trying to recall here.... wasn't the BAT bar the same diameter as the stock bar, at 19mm, but BAT said they used some heat treatment to increase stiffness? If so, what a load of garbage.
I seem to recall we've been through this discussion before, and it went like this: if the BAT bar is the same diameter as the stock bar, then the stiffness will not be any different. Hence, there will not be any handling effects. If you want to look at this in a positive light, at least that means the mount loads won't go up, and hence the subframe will last.
As an engineer, I can't imagine the geometry bits, end stops, whatever, that BAT describes having anything to do with subframe durability. Take a look at the stock cantilevered mounts, and it is easy to see why larger bars lead to failure.
