OK don't laugh but it has taken me a month and a half and almost 2,000 miles to figure out that premium is the ideal fuel for this car (a literal reading of my owner's manual implies that 87 is recommended, with higher octane for towing and other extreme use). So I tanked up with 93 since 91 is not available at my usual gas station. While I am not sure I noticed an 18 hp SOTP difference, I did notice the following: - the "flat spot" at low RPMs seems to be less apparent, and may even be gone. With 93, a couple of times so far I unintentionally broke the tires loose on dry pavement when accelerating up through first gear mid-throttle. It didn't seem a lot faster but the power seems to come on slightly earlier and more evenly. - the car used to occasionally lurch when cold if I didn't give it a little more throttle, either when backing out of the driveway or starting off in first. Nothing bothersome; I figured I was just getting used to the car. But now with premium fuel, that characteristic seems to be gone for the most part. I was curious if anyone else has had this happen, or if I am imagining things? I figure anything is possible with the computer adjusting the air/fuel/timing for octane. BTW I have 3.31s and the car is 100% stock.