RCX makes the 5" RCD makes a 4" http://4wheelonline.com/RCD4WDF150SuspensionLiftKits.4920.29383 Them terra grapps will work fine!
Short video of a little mud hole. Got more rain yesterday so we went out again last night and could really do some donuts and stuff in the field. 2002 F150 Mudding - YouTube