I agree with everything InCommando said in regards to 4WD.
In regards to the hood guard. It will protect the front edge of the hood from stone chips, though you may find that now instead of the stone chipping you hood paint, it now bounces of the hood guard and hits your windshield. The main draw back I had with them on a previous truck is snow. If you live in an area that gets snow, and you don't clear the snow out from under the hood guard because you are lazy like me

, then it ultimately turns into a chunk of ice and causes premature rust on the front edge of the hood.
If your hood has soo many chips that you are considering repainting it, then instead of purchasing the hood guard I would personally rather use spray on rock guard on the front of the hood, and then paint over that with the regular hood colour.