In an earlier post I had mentioned that our LS was sputtering - sort of a hic-up when accelerating. Some of you suggested that this could be a spark plug issue - for which I have the parts to swap but have yet to do so.
In anycase me being the cynical type, I was putting regular fuel into the car when I drove it. My wife was as well (it's her car). She decided to go with the recomended premium and according to her the car seems to "hic-up" less then it did before.
So I guess the fuel really does make a difference?