5.9l Cummins Mod Suggestions

I've owned my 2003 5.9l for about 1.5 years now, and I am looking for suggestions on mods for longevity. The truck is bone stock other than an exhaust. 230k miles, auto trans. Original motor and trans. What modifications should I consider at this point if I plan to keep the truck forever? I've heard that an aftermarket lift pump and cold air intake could help. I also believe it has the original injectors. Should I be replacing those soon, and if so, should I go stock or upgrade? I don't want to push any more power or anything; I just want the truck to last forever.