get the adjustables. You will be happier down the line. also, it will allow you to get a lot of your caster back thereby allowing for a better alignment.
Ideally, once the mod bug has struck, you will want to get adjustable pieces like the track bars and control arms as you may one day want to go higher lift wise. if this the case, you can use all of your linkages with new springs or spacers. this is all assuming you stay with a short arm setup or don't go crazy with 6" lift springs or something.
2008 CRD GC