I added counterweight (60g) to my 4.0 last night. I had a real problem this year with putts missing left and I'm hoping this helps stabilize the stroke. It feels good after a very small sample. I changed the face plate a couple of weeks ago (to a double line on top, nothing on the bottom) and that seems to have helped me aim straighter. Really looking forward to spring, but it's the hope that kills you.