Jeff, I used the Rough Country 2" wheel spacers but from my experience you can find them a little cheaper on Amazon or other websites. Here's the link for the RC spacers: http://www.roughcountry.com/wheel-spacers-1101.html Obviously, you will need to buy two pair. I have used these same spacers on my last two FSCs and have not had a single issue. Mind you I dont do alot of offroad driving. Never had any vibration issues. On the front wheels, there are little copper keeper rings on two of the factory studs that help aid the install of the factory rotor. Make sure u remove them otherwise the spacer will not sit flush up against the rotor.
Ill take some pics down the side when I get home tonight.