You will feel the difference. Now mind you it's not an earth shattering, jaw dropping difference, but your acceleration will be a bit quicker, breaking will improve a decent amount and conoring will improve as well. Remember you'll be about 250 lbs lighter as well. Now you car feels like it accelerates quicker w/ the skinny 15 steelies because in part they are skinnier, but mainly because the circumference of the tire is smaller. Remember, your wheels/tires are part of the drive line as well. They are like gears. A bigger wheel/tire setup will decrease acceleration, but increase top speed per RPM. A smaller wheel and tire set up will increase acceleration but decrease top speed per RPM. It might seem confusing, but if you think about it, it will all make sense.
