im new to diesels and i was wondering what would be the first thing i should do performance wise? Its pretty much a stock cummins its had the regular maintenance kept up pretty well.

 

exhaust, intake, and gauges.

 

gauges first, silencer ring, intake, exhaust, fuel plate, starwheel adjustment,
nevermind you have a firstgen so gauges first, silencer ring, intake, exhaust, tune your pump, fuel pen, and probly a turbo upgrade if you have h1c still hx35 spools a little quicker and makes a bit more boost but its not a huge difference

 

guages, bhaf, throw your muffler in the trash, tune your pump. All for under $300 if you search