Originally Posted by rknight111 
They don't include those with the Diesels. My truck only has 20000 km so I cannot really comment on Fuel economy but its going up my average right now is 13.9 City and Im not sure on the highway yet as I have just pulled the trailer only on the highway. I now chipped it to help with fuel economony.
Otherwise getting back to the supplimental cab heater, I would not forget to add this to the option list if you live in Canada or the Northern USA.
Man, I hope that 13.9 is l/100km and not mpg. I get about 10 l/100km highway and about 13 city. I get about 13 -15 l/100km with two sleds on the deck highway (depends how fast I go, speed really affects it with the sleds on). I have an 03 CTD dodge though.