Three years now I have had my Ram Eco-Diesel here in Colorado and only twice have I run into fuel gelling issues but the temps were south of -20 degrees F. In three years, I have never utilized a fuel treatment of any kind. My truck sits outside, as the motorcycles get the garage. I do have a block heater, and always "plug in" on cold nights. This weekend we are supposed to have temps dipping to the negative 10 mark or lower and I thought I might add some treatment, but I have some questions. 1. If you are in a cold climate, do you always use a fuel treatment all winter, or only when the forecast is showing very frigid temps? 2. Is there a particular brand of treatment that is superior and even multi-use, in the fact that it also cleans up the injectors, etc.? 3. Seems I have read that some drivers use certain treatments that are great for pre-2007 diesels, but the newer engines shouldn't use. Is there anything to this claim? 4. Having a modern V-6 turbo diesel that has a DEF system.... is that an important consideration in this decision? Thanks for the help!