what do I need for a 4/6 drop?

Edited: 9/23/2004 8:17:26 PM by twankydeuce

I already have a 2/4 drop on my truck with springs and lowering shocks up front and hangers, shackles and shocks in the rear. What do I need and What can I keep for a 4/6?
btw its a 2001 sierra