I had it and a uni filter installed and the initial throttle response was a great improvement.It will pull the front wheels up without pulling back on it now.It will still go 64 mph but it seems to be a little sluggish getting there now,I raced a buddy on a stock Rubicon and lost!!!I have a winch,2 mud light tires (on the rear) and a box carrying approx 10 pounds of stuff.I only weigh 170 I don't think I should be losing too a stock Rubicon.Any advice would be appreciated.