I suspect that you are shooting with plenty of speed already. The bows of today, even one that is a few years old shoot much faster than the bows of yesterday that killed lots of deer effectively. Don't believe the hype that you need to shoot 300 fps to kill a deer. It is a lie. As long as it is cranked up to at least 45 Lbs. you should be fine.

The only thing more speed will do for you is bring your sight pins closer together (arrow drops less at each distance).

I was under the impression that anything you put on the bow, including limb savers and string silencers actually slowed the bow down a little. Did I hear wrong?????