We weren't thrilled with the way the bolts are attached to the flares. Using Bondo to attach the bolts to fiberglass seemed a bit butch to us, and the warning scared us. While the 1/4-inch-thick fiberglass flare will take a rock hit, we aren't so sure if the mounting method will handle it. Epoxy may have been a better choice. Even with the warning, the only bolts we managed to break off weren't due to over tightening, but to having cut through the Bondo with the angle grinder while trimming the flare to clear the rockers and then slamming the door without checking for clearance. Iceland Offroad told us that they tried forming the bolts into the flares, but it just made it too difficult to pull out of the mold and that the flares should handle the occasional impact with a rock or a tree just fine. We feel Iceland Offroad goes the extra mile with the attachment hardware included with the fenders. Not only were fender washers included, but so were Nylock nuts and rubber washers to keep out water.