It is true, the gasoline is different now days and the rubber ever so much. Also to begin with the stock Z tires were pretty crappy to begin with, so it really knocked the Z's true performance in acceleration one, but mostly grip and handling! Hell, look at how well Z's ran the slalom and other tests 0-60's 5.0secs many times with those crappy tires! Imagine if you had the Piot Sports or Bridgestone Pole Positions S0-2 instead.....