Not to steal the thunder. Think hard about what kind of 4x4ing you are going to do. Cranking the torsion Bars and dropping $600 on better tires will not give you significant results.
Before you spend any money on Mods on a 2x4 consider a trade in. I would sell privatly and then take advantage of the deals there must be in your area for 2001's....
4x4ing in an X you will find that you become a more responsive drive on road as well. I value the times (although not as much time as I want) where I have been out there doing technical stuff.
C