I know that refiners put additives into pump ULSD. I imagine they also put additives into ULSD #2. When you said this:

...Lubricity is the other issue, although if you're burning LSD #2 it won't be as bad. Once ULSD #2 is delivered (and soon enough you won't be able to get anything else), you probably want to keep it out of your system.... '

I thought you were implying that ULSD #2 wouldn't provide as much lubricity as pump ULSD, though in retrospect I guess your statement wasn't very clear. In any event, *that* is why I was asking about using an user-placed additive: because of what you stated/suggested. I still don't understand, but I appreciate the input.