I've installed a 1" BL and helped install a 3" BL... different vehicles, similar process.
Things that had to be done with the 3" that did not have to be done with a 1":
Lengthen the steering column
Extend the filler hose and vent hose
Possible body work to regain 2, 4, and R
Extending the shifter so it doesn't look like a shorty.
putting a new bracket on the 4wd shifter (both require this)
Modifying your fan shroud (both require this)
Not to mention its going to look really funny having a 3" gap between your body and bumpers