I am at about 289,000 miles on my "05" Cummins. I have to say, it SEEMS to be quieter, and run a tad smoother when either some TC-w3 2 stroke oil, or some stanadyne is added to the fuel.
Yeah, it is just my PERSONAL opinion, and perhaps not scientific, but that is also something I have seen, and recommend.
My experience with the 04 Ford Diesel, is.....good luck!
Hated ours for replacement of studs, heads, turbos, and all the heating.....Dealer took mine back as a "Lemon Law" junker.
Then bought my Dodge Ram, Cummins.....the end.