Buying a crank pulley is definitely worth every penny. I have an Unorthodox crank pulley and I can actually FEEL a difference once I installed it. Considering the stock 1.6 sohc pulley weight of 6 lbs and the Unorthodox pulley's weight of 0.5 lbs!, you are saving 5.5 lbs of rotating mass off of the crank, which in turn helps the car rev faster and have a lot less load under acceleration. The gain in HP is not really from any under/overdrive of the pulley, but instead from the weight savings, when you're talking about the crank pulley. Other pulleys such as the alternator, and P/S pulley gains power thru underdriving, not weight. I have had Crank pulleys in two previous cars and everything ran perfect. No dead alternators. But only the Unorthodox pulleys are worth the money. Other ones are junk.