I just traded in my stock 2007 6.7. I loved everything about the truck except the terrible mileage. I was getting 12-13 mpg in the city and 13-14 on the highway. I just couldnt bring myself to spend close to $3000 dollars (including installation) to improve the gas mileage on a new truck. It wasnt that I couldnt afford it or didnt have the money... it was mainly the principle of me being force to dump more money into a new vehicle just for me to keep it. I got a brand new GMC Denali for about the same price that I paid for my Dodge (I did lose my as* on the trade). The Denali only gets about 13-14 in the city but does get 17-18 on the highway not to mention 60-70 cents a gallon cheaper than diesel. So everytime I fill up, I save about $20. Just wanted to give me two cents. Its sad what the EPA has done to deisels.