I have the WRP pulleys on my truck. I did notice a pretty decent gain with them. Truck seemed to rap out faster and with less effort. I don't think WRP is selling them anymore, at least around here since he got a bad wrap on some of products and customer service. I really do like my pulleys though. I have had them for about 10K miles so far. If you can find a person that is selling them, I would snatch them while you can.