yea the fiamma don't like to be twisted
most ones i know of have been mounted onto utes with a solid backing normally of aluminium (custom ladder rack headboard)
you will still need to peg or rope it down as the wind will pick it up and bend it over the car
if you break the arms replacements cost big $$ as you have to but the complete arm assembly
set it up properly 1st time and it should last
Adam