Before I did my first oil change I did some searching. What I found was this stuff.
http://www.valvoline.com/pages/produ...sp?product=113
It made a huge impression that Cummins was willing to lend their logo to the labeling of the product. Anyhow, I've been using this product in my PowerStroke, and in the past I used it in my Cummins w/ fine results. As far as additives in the "oil", I vote no. However, I use additives in my fuel. I've been using a combo equal to about 32oz. of "PowerService&MarvelMysteryOil" in every tank of fuel. I believe this is also doing some good things for the fueling path of my P.S.D. Oh yeah, there seems to also be a consensus among the PowerStroke and the Cummins guys that "FleetGuard/Stratopore" filters are at the top of the heap.