Just got my first fillup of B99 in my 2005.
Only put about 60 miles on it, and it's problably a mix of around B40 with the #2 I still had in my tank.
Of course I also filled up the bed tank, so I have B99 to fill from when this runs out.
Man, that stuff looked more like maple syrup then diesel!
Of course I actually didn't mind the smell of biodiesel. Not that #2 is bad, but the bio is even better.
I will try it in the 2001, but only when I have a couple extra fuel filters handy. With over 120k miles onit, I am sure there is plenty of crud built up in it.
Personally, I think that getting at least a B5 to B20 mix will greatly increase the life of our VP44s and CP3s. Cummins is just being safe in their approvals. As it could cost them a LOT if they just say that B100 is fine for everything and something goes wrong.
Something else to think about, with the newer lower sulfur fuels coming out, the bio will really help keep our injection pumps lubed like they need.