I think the cost of repair argument isn't that relevant and I would expect that all D4 owners have their car insured..
I think the main point is can you get home after you have hit something? After all isn't that reason we fit these bars?
I don't know what grade of alloy the bar makers use.... However there are some grades of alloy that are extremely tough.
The front bar is my next addition I am still deciding what type of bar to fit.

