if you are talking about a Aluminum crank pulley, i acually have not put one on my car yet but i do plan to in the near future.. i was told it is one of the best things you could do to your car, the stock pulley is about 4 to 5 pounds and the aluminum one is only 1 pound. which takes stress taking off of the motor. your throttle will be increased and so will your horsepower, if you got the 100 dollars it would be a great thing for you to do for your car.
you can get the part at
http://roadracemotorsports.com