I use the regular unleaded in my Land Rover, it does not make a difference, now if you go on a long trip you can tell that you get better mileage. Looks like the same truck fills all the tanks at the gas station.
2000 Ford 7.3 Powerstroke 4x4
2006 Mazda Tribute
1983 Black 300 D (donated to charity)
1993 Teal 300 D (160K) Sold
"I love the smell of burnt diesel fuel in the morning, it smells like ....VICTORY"