I would say the Kumos have average dry weather grip and good wet weather grip. This is 255/275 on 17x9 and 17x10.5. I think I'm getting some vibration from my fronts with about 5000 miles on them. Vibration seems to vary with temperature and is felt at about 75 mph. Supposedly the balance is good. My other wheels/tires don't have the vibration.
Jeff
Jeff