I have been looking for performance parts to change the spring characteristics of my driver, and found the red and yellow springs for the series 40 driver from mfgsupply.com. What are the differences, (red says 28# and yellow says 14#) in the engagement rate of the drive clutch? I need a spring pack to engage at a higher rpm to get up in the power out of corners. Thanks for any help. I think the red springs are the higher rpm springs, but I would like a second opinion. 
