Dude ... its ROCK solid.
Its made out of cast iron and hard plastic shit . ... and everythign fastens up extremely tight too
I would have no problem hanging off the side of a car ....
The only issue I have with my set up is 1) Wind vibration onto the camera and 2) Flexable mounting surface ..... ie .. rear cowl

... Was too heavy so it bounced alot.
IF I had fairings .. would not be a problem.