The performance gains are there, they are just not as drastic as I thought they would be. The car is more fun to drive on the street and the power band is more readily available but.. After all was said and done I paid over a grand for the gears (which I got for $475) that included all the seals, shims crush collar, 6 quarts of fluid and install. I would put the gears on the same list as the RPS flywheel. Sure it's nice and made a little difference but it was almost $500. I think I would have rather had a nice set of lightweight wheels instead. just my 2 cents