X2 on no programmers...
When I bought our diesel used, it had a programmer installed, though I did enjoy the tremendous power and response out of my truck I deleted it shortly after.
When you do your research on these products and how hard they are on "stock" components on the truck, longevity is compromised. I frequently visit the diesel forums and you can see the evidence of this all day long.
I'm happy with our stock MPG and plenty of power it provides without being jacked up!