The solution is simple - use #1 Diesel. It's gel point is -40 F or C. You don't need heated filters, or heaters in your fuel tank and all of the wacky additives. I can't understand why people go through all of the wacky solutions they do, like the ones above, when there is a very simple. I guess most people can't get enough pain. Have you never heard of #1 diesel? If it is colder than -40 - stay inside. #1 diesel have very little lubricating qualities, so a lubricating additive would be helpful.
Save your summer diesel blend for summer.