I think the only concern with running B100 is that the oil could possibly get diluted while doing a regeneration since the extra fuel is injected during the exhaust stroke and biodiesel has a higher flash point so it would have to be very hot in order to burn. The new 2011 Duramax now has an extra injector in the exhaust to eliminate oil dilution. Other than the oil issue, the biodiesel should run perfect in the new 6.7L Powerstroke.