Rog is right. Again....
I beat this up on the other board about what you get out of it. The bottom line after riding is you get excellent RPM range on hill climbs, higher top speed, and no loss in torque.
If you only did the sheave alone, you would be MUCH higher on top speed. But doing the sheave alone actually will impact your climbing ability. By doing the duners kit, you will be a few MPH faster on top end, much better climbing ability, and a bit of a punch off the line.
Best all around mod I ever did. So far.