are all crank pulleys the same, or should i be weary of which one to buy, i found one on ebay for 30 bucks, and one right next to it for 120. any difference, and if their is which one would you guys recommend
Just get a lightweight pully rather than an underdriver pully. And underdrive has a smaller rotating mass which steals electrcity and such from your car. And underdrive pully generally weighs 4 lbs less and takes the equivalent of 100lbs off of your car due to the lighter rotating mass. 100lbs = 4HP give or take.