I try to use Shell fuel; I'm not sure if it is superior to the competition, but it seems to work well with the vehicle. I don't always use V power; however, when I had the 3MPS, I had to use it in that and if I didn't, there was a noticeable drop in power, but then again, that is probably because it is a performance vehicle. I'm not sure if it will make much of a difference to the 6 2.5, but I will try