I was thinking that a way to install a leveling kit without getting vibrations would be to drop the diff as well. I found a diff dropping kit online for the previous generation trucks, it just uses brackets where the diff attaches to lower it about 2 inches. I couldn't find anything like this for the current generation trucks, but I think the front 'axle' is the same. Would I be able to get away using them on my '11?

Or is there a place that sells just the front crossmember from say a 4" lift that could be installed with the leveling kit, or would that drop it too much?

This truck won't see any offroading, I have a built jeep for that, I just want this one to sit level.