I broke a 5/8" grade-8 on an upper link in my rear 4-link once. I'm afraid to look at that pic of that goofy adjuster thing too closely, for fear of breaking it just by thinking too hard, let alone wheeling too hard.
I'm surprised it took over 7 pages for someone to mention shear strength. That's like a new record, Wiki must have been down for a while.
My XJ was once on undropped shortarms with 4.5" lift for like a whole year and a half; I didn't die. I also drove it on the road all the time and once it even got a BA RTI score. I'm also not ever building anything with short arms ever again.
But my next race rig is (seriously) going to have a Dana 35 under it, so WTF do I know.
edit: and for the record, my short-arms-and-4.5-lift was done the old fashioned way, before everyone and their mom had solidworks and a plasma CNC. I kept stock uppers and used adjustable lowers to put the caster back into spec. No goofy adjuster thingys here!