These guys are right about early vs. late model 01 Stangs being a little different due to a change over in the water pump pulley. Go to Steeda's site and read up on the difference, then check your car to see which water pump you have.
Ditto here too on what the guys said: Steeda is the best for pulleys. I was gonna get some Steeda's myself till I found out it reduces the efficiency of your A/C. Call me a wus but I just can't do weak A/C in Tucson, AZ.