Depends on your required length of pull, you can leave the OEM pad on if it fits you better, or remove it. I prefer the Limbsaver prefit pad, the 10011 fits the new style checkered syn stock by relocating the bottom screw, and the 10018 fits the old style. Most synthetic stocks are hollow, makes a nice place to add weight if needed. I stuff it full of closed cell foam to help deaden it. You can also use expanding sealant foam if you make a way to access the stock bolt like a piece of PVC pipe.
Tim