Here in Wyoming we have the Low Sulfer now as well, I dont drive a deisel but I have plenty of friends they see a difference in power and mileage. Whats worse is that some of them even have the bed mounted Fuel tank. 60% of our Fuel stations will only allow a certain amount of fuel to be purchaced at a time. so you have to go somewhere else to fill your Auxillary tank if you need to. It really is stupid that they have to go somewhere else to buy fuel after they already filled up. My Boss drives a Dmax 3500 and just bought a 150 GAL Fuel tank. it cost him the last time he filled it about 345.00 about. WOW <img src="/forums/images/graemlins/scared.gif" alt="" /> That and he had to go somewhere else to finish filling it. But one thing they will all tell you is a differnce in power and fuel mileage. I dont drive a deisel so I cannot back up the claim's. This is what Im told.