Ok, this is not a V8. It is an inline 6 Cat C7. Cummins just announced its new models already meet 2010 emissins today. This has been achieved with the fuel systems and the new soot-stopping canisters; not to mention th recirculatory exhaust in place. The problem diesels always had was NOx and soot levels. . . unburned hydrocarbons is that black smoke you see in over-fueled engines or engines that have been heavily modified. New diesel engine have none of those old attributes. In fact the reason class 8 trucks have smoke stacks that are verticle is because it looked like they were on fire back in the 1930's because of the excessive unburned hydrocarbons. This problem was solved by verticle stacks so people in regular sutos would stop calling the fire department. This was happening in San Fran. The Supertruck is great for he application is was designed for.....moving weight (supplies, boats, material, people). Then it has a purpose. Large people mover transit buses are no different, though most are part electric (seattle) or CNG (compressed natural gas). See Westport engineering for more info on CNG.