The B20 will likely be okay for our engines but I read somewhere sometime ago that it packs less energy so will probably adversely affect our mileage. But it should be 20c to 30c cheaper per gallon to offset the mileage reduction. Many states now have requirements that diesel fuel sold at retail must be 10% to 20% bio. Another downside to high percentages of bio in diesel is it will gel at higher temperatures... so in late Fall through early Spring, it should be thinned with stove oil. In Montana, for example, Winter blends of retail diesel are common. And, of course, stove oil in Winter blends will add to the cost. Yet another issue is with higher bio percentages, the fuel filters will probably need changing more often.