Sonner, I bought a pair over the summer, and took them off already. I bought them primarily to quiet my bow and not for speed. I was getting sick of the leeches breaking for me. I used all four of the spiders. But, I really didn't like their effect on noise. The leeches worked much better. So, I coughed up the money and wentr back to the leeches. As far as spped gain or loss, I didn't notice any difference. But remember that I used all of the spiders provided.