Does anyone know if there are places to buy biodiesel in northern IL or IN? Was reading an article in a magazine from my electric co-op, and they said the cost was "comparable" to regular diesel. They've been running it in co-op trucks in southern IL for a year or two with good results and like that they are supporting the farmers. They also mentioned that blends up to 20% bio could be used without fuel system mods. Is that true of our Cummins?