Have enjoyed owning this vehicle so much and Toyota's reputation for quality and reliabilty are well-founded. The pickup rides almost as good as any comfortable car but will go places an auto and most trucks can't think about.
Power!! Sunroof, on the fly 4 wd, reliabilty, amount of fun to drive!
I think only necessary improvements can be a very good aftermarket gas shocks (Bilstien) unless you get the TRD off road version which has them, good set of tires (Pro Comp's All-Terrain are the best I've ever seen, wet trac. superb, mud & snow as well w/50k mile wear warr. even on 31-10.50x15's)