You only need the front fender flares (51-71-7-051-037 and -038) if you want your 4.8is look like the European version. Otherwise, you won't need them. The US version only comes with the rear fender flares.

The Aluminum Running Boards are the same for 3.0, 4.4, and 4.6is or 4.8is. Like LeMansX5 said, you just need to buy the extra fender flares for your 4.8is because though the ones came with the running boards will fit the 4.8is, they are not the wider flares like the ones that came standard on your 4.8is.

And do buy the extra rivets if you plan to do it yourself. They break easily and you can use the extra ones.