I've been working with Volvo for the past few months getting some specs designed from the factory and Volvo engineering is working on an option for us for a factory designed, not sales person designed expeditor using the VN780 cab/sleeper. They are really being stretched because we have them a 33,000lb max gvw and a payload of around 10,000. That said the Volvo Engineers said not to use the D11, that it's really designed as a big vocational engine and that the D13 would give better fuel milage, lower maint cost and longer life span. I didn't realize the D11 was designed as such and was keen on going that route until they let us know this information. Just thought I'd pass that along.