If you want to pull the most power from a diesel without ripping in to it, programmers are usually a good buy. And if you live in a state that doesn't have emissions, there's no worries about that. Plug and play basically.
Depending on the diesel engine and brand truck, you can add too much power with a tuner. 6.0 Fords can have problems with head gaskets if your tune is too hot.
Depending on the diesel engine and brand truck, you can add too much power with a tuner. 6.0 Fords can have problems with head gaskets if your tune is too hot.