well prolly a bit more than that would take to bend it, its just if you land wrong without them it will bend, and lets face it when your new to jumping you land poorly ALOT The stock plastic ones on hard impacts flex and thats why the chassis bends where the alum ones are rigid , and extremely solid. Now if your driving with 0 intention of ever jumping it the plastic ones would probably be fine, but from experience driving on flat surfaces gets old FAST and you start sending them flying

guy that told me about it him and his friends were jumping suburbans and crap (hell they got a savage stuck on the roof of their house to show the kinda bashing they do)