Old man Dave that is a question for the guys that purchased them. I have no idea why anyone would pay three times the amount of a stock harmonic balancer to get an ATI when their getting about the same product in the end. Rubber balancers from factory are tuned specifically for that engine and its power and rpm parameters. When you add performance parts to your engine it changes that original power spec. Most guys also increase their rpms. Since Fluidampr is a silicone based damper it tunes it's self through all power and rpm ranges controlling the harmful torsional vibrations created by your engine resulting in a smoother running engine which FREES up lost power. Fluidampr does not add horsepower to your engine. With the addition to our harmonic balancer we are able to have your engine run smoother and better therefore freeing up that power that was once lost. This is why you see the expensive exotic cars coming with a silicone style damper vs the rubber balancer, along with large farm equipment such has a half million dollar tractor. You can find silicone dampers from the factory on these units. They need those to run nothing other than perfect. No time for breaking down in a field that means you and I won't eat! And again if you need more information shoot me a message I'd be happy to help.