I just removed the two nuts off the top of the suspension arms, put the brace on and then tightened them back up.
I think the reason for the "damage" as you put is because the turrents are slightly narrower than the collars on the brace hence the movement. I think had the turrents been a few millimetres larger then it wouldnt be such a problem.
Obviously if you have OMP looking into it, then yours must be REALLY bad damage coz those photos you had were pretty minor imho.