Oh ok, yeah it has more torque for sure especially for turning larger tires. I also use mine to pull my dirt bikes on a small trailer which it does with ease.
Your $75 per year figure will be different for everyone depending on how much they drive and how they drive. There is no way to put an accurate number on yearly fuel savings.
Right, I based that on 7500 miles per year (my likely mileage for something like the samurai), fuel prices of 3/gal unleaded and 3.40 diesel, and mpg figures of 25 and 35. Generalizations of course, but assuming it would cost, total, 750 for the gas swap and 1750 for the VW diesel, it would take 13 years to account for the extra $1000, not including inflation and fuel price fluctuations.
Of course, economics is not the only reason to do a diesel swap. You get more torque, higher towing and climbing capacities, multi-fuel capability, and increased long-term reliability.
Just trying to iron out the benefits here, as it seems many are apot to jump to "diesel swap saves money," without really thinking about the whole picture. It does not, in fact, save money--or is a wash, depending on which figures you calculate in.