I've had that problem.. the cusco RSB is 23mm thick.. i hit the rear wheel on a curb turning going around 30km/h and the endlink connecting to the lower controller arm ripped off.. had to totally replace the lower controller arm as u can't weld it back.. and bought that metal plate from Corsports to reinforce it so it wont rip off again.. and better yet dont hit the curb on the rear wheels