I have no doubt the oem 3" hitches are well designed and plenty strong enough when used as intended. When I was crawling around under new trucks investigating the ford oem hitches, I could tell they used high strength steel just from the sound they make when getting pinged with a screwdriver. Sounded like heat treated and/or high carbon content. Also, the 3" hitches were made of thicker steel than the 2-1/2" hitches. I measured the sideplate thickness and seems like one was .170" and the other was .210".....or something like that.
bradw