Where do you store your tractor? I live in Northern Minnesota and keep my tractor in a heated garage. I keep enough #2 diesel to last through the winter and have never had a problem using my tractor in temps to -40. The secret is the warm tractor to start with. The fuel injection system has a return to tank so fuel stays warm as long as you are running. Last winter, however, I did a lot of cleanup work for my cousin and filled my tractor from his farm tank which is #1. A difference is fuel economy goes downhill. Second thing is the lubricity of #1 is not as good as #2 so there is possibly more wear using winter fuel. The reason that might not be a problem is you have a Kubota, a Japanese tractor with a Japanese fuel injection system. Japanese diesel fuel lacks the lubricity of our #2 so their fuel injection pumps are extremely durable in low lubricity conditions. I am speaking in generalities here because of having to supply machines to Japan. When participating in a discussion with our engine division regarding lubricity and fuel injection system life (which is lower with #1), I became personally concerned because I had just purchased a new Kubota and living in a place where you get #1 from November through March, it could be a problem. The engine division people told me to forget about it - I had a Japanese engine and they make their systems to run on almost zero lubricity fuel. It is Western designs, like the one the whole worldwide meeting was about, that had the concern.