Believe it or not, they changed my tiller tune just slightly. Without them I was getting bullets holes thru the paper at 5, 10, and 15 yards. With them on, I started getting a slight tear. I readjusted my nock, and now all is fine. I also lost 2 to 3 fps on my shooting chrony. Some people have actually gained speed. I bet I didn't get them perfectly in the center of the limb, or not same distance from my string. Either way its fixed now.

I have to admit, it was a worthwhile ad on. speed and retuning and all. Really quieten down the bow, and lowed shock slightly.