Your going to want to start your build by increasing the air flow for the engine. The way this is accomplished is by getting a higher, more effciant flowing intake and exhaust system.
Next, ur gonna want to replace the stock exhaust system with a larger aftermarket one. The best exhaust , I've heard, in the area of power is going to be a 4" diameter straight pipe with 4" dp ( downpipe ). Just remember that the less pipe the exhaust gases have to run through means better air flow, which equals more power. On my truck I ran a 45degree elbow that goes right in front of the back wheel. This cuts off about 4-5 feet of pipe and therefore gives better flow.
After you do these mods then and only then should you start doing stuff like fuel modifications, unless u want a toasted engine.�� When you start your fuel mods you should invest in a couple gauges like and EGT (exhaust gas temperature) guage, turbo boost guage, and if you have an automatic tranny, a transmission temp guage.
Gale Banks, a aftermarket specialst in the area of perfomance diesel parts, once said: 'If you haven't increased air flow you have no business messing with fuel.'
Hope this helps
P.S. don't get a K&N air filter as a choice for your diesel truck. These filters are not up to par for turbo diesel trucks and will most likely dust ur engine .