Do not use the PD impeller, it puts serious load on the drive gear and actually it cools worse than the stock one, The only way to make it work better is by taking 2 fins off of it, grind them down!! I know the stock one is plastic but when its maintained properly it will not fail. correct jetting, good coolant and no play in the mounting are all factors in the life of the stock impeller and if you dont believe it robs power, put it on a dyno. I couldnt believe it myself but it does.