^ It is a costly upgrade but definitely worth every penny, nickel, dime and hundred dollar bill you spend.
It is a task that you need to know what your doing and take your time doing it. Time and patience is needed to make sure that you are shimmed properly so that the gears match/ mate with the right amount of space between them.
But then after the gears are bought you might as well purchase lockers because you'll probably need carriers.
Just my thoughts.