some with pulleys and some with stock pulleys and I have yet to see a motor with unusual wear that I could say was due to the pulley. In fact I have seen motors that have worse wear with the original stock pulleys still on them. It is more of how the motor was treated than if it had a pulley or not. You can tell how a person changes his oil and how hard he drives the car by inspecting the bearing and 99.99% of the time it is poor maintenance and harsh driving that causes problems *NOT* a pulley or other upgrades. Just my $.02