The people who say they can "FEEL" a difference are morons. On my stock engine I run cheap-o. Once i get my good motor i run premium if I am going to run it hard and mid grade for daily driving. If your car is tuned for a specific fuel rating, stick to it. I've been tuned for 93 but have run 101 and C16. Didnt do any difference b/c the car wasnt tuned for it.

-Ant.