from experiance i havent notched mine and i have a flip kit, i hauled 3 dirtbikes to maine so roughly 250 miles on not the nicest highways, and thats about 600lbs and a kid in my passenger seat, and it did fine with no bottoming out, its not a necessity, but if you going to tow, or have alot of weight in the back part of the bed, then yes i would notch it, that or if you remove your overload spring