Yeah I can say for sure that the bump up to 58 gave the overall setup a crisper feel... the racquet was still soft enough so I had a sense of where the ball was, and how on-center a shot was, but the tighter strings gave me the confidence to hit out even more than usual. This confidence was huge on my backhand return, which ordinarily isn't my strongest shot, but I was able to really swing through the ball and get a good fast arc on it, so the opposing doubles team couldn't attack on a serve. As an individual, having that solid of a day on the backhand was huge, because the other team couldn't attack me with a serve. (Ordinarily my forehand is the shot opponents avoid more, and maybe this was why they kept going at the backhand even though I was killing them with that shot.) I think at this higher tension the ability to swing out with this racquet is increased, which is nice because my particular setup has a lot of natural power. I don't know if I'll keep increasing tension or not as 4g is a fairly stiff string and I want to preserve my arm, but I'd call the increase in tension from 55 to 58 a success.