Forgot to add in the cold weather issue of gelling diesel fuel. Diesel is thicker and will start clouding at 40F. It can start thicken up enough at 10F to interfere with starting or running. Diesel owners use additives like Kleen Power Diesel or Howe's or Stanadyne to prevent gelling, kill algae, lubricate injectors, and seperate/disperse water. We also use engine block heaters to keep the coolant about 50 degrees F even in a deep freeze. If you live up north, consider the engine block heater in winter and keep an extra fuel filter or two in the vehicle. If you gel up, you will mostly likely need to pour in Kleen Power Diesel 911, wait, remove fuel filter and replace with a new filter, try to crank again, etc. Worse case is a tow to an indoor facility to thaw out the diesel fuel. That's why truckers run the engine the entire night in winter.
Fuel up in stations that go through a lot of fuel to reduce water condensation in diesel like truck stops. Flyers, Loves, TA, Flying J were on my list on every road trip. Most additives can disperse water but water disrupt engine perforamance and damage parts, and diesel parts are expensive. Bad fuel is also a bane of diesels as they are more sensitive to fuel give the higher parameters of performance and emissions standards. These are not the smoky low powered tractor engiens of yore that can run on motor oil, peanut oil, or kerosense mixed in. They are much more finicky and with injectors running at 25,000-30,000 psi, diesel fuel must be clean and pure.
Many folks are not aware of what it takes to keep a diesel happy and end up being unhappy owners.
I believe some of the VW diesels can hit 45 mpgs, 40 mpg with just some judicious right foot action. Of course the diesel Passats, Bugs, and Golfs are rated at much lower numbers, around 230 pounds of torque and 140 horses. Notice the 3.0 liter Toureg mpg drops to 29 mpg when tuned to near Jeep numbers.
Big difference in power. You pay to play.