Drilling a hole in the bottom of the front frame rail will not hurt a thing. Yes they do warn the public about drilling in their new hydro-formed frame rails, there are many areas that will cause trouble if not done properly. The front lower section of the frame rail is not one of them, the small bolt needed for the hitch is fine. The drilling in even high load areas is exceptable if done right, mostly you just have to use a inner frame rail bushing. This keeps the frame rails from de-forming or pulling in together when the bolts are tightened.