Most of the rear tower breaks I have seen have been in that same spot. My theory is that it can press on the motor mount in a crash and this causes it to break. I spaced my tower out by 1mm using some washers and this improved matters no end, having had a couple of rolls that I would have expected to break the tower. I eventually decided to run a CF tower and the washers in order to further improve my chances of surviving a crash! There is a small mark on the CF tower where it must flex and touch the motor mount so there must be something in my logic...!
I also have CF steering linkage as I broke one just clipping a corner (HD ball cups stayed fully intact
).