Scangauge or equivalent
EGT gauge (almost mandatory for towing esp in gnarly/sandy terrain)
2.75 or 3 inch exhaust
Catch Can
More efficient intercooler
Manual Boost Control
EGR block (you will need Man Boost Control or VNT adjusted and ability to clear MIL with a full EGR block)
Rear Coil Tower braces
ECU remap or chip
2 inch lift or better rear coils & shocks at minimum (if you tow in soft sand on stock suspension it will drag its arse like a dog with worms )
Snork can wait till you have the $'s and be wary of fuel prefilters on the CRD, they have a very low micron filter stock and prefilter can be either of no use or possibly cause delivery issues to the pump