Just bought these tires to replace my Kumhos. The Kumhos had fantastic tread life, but they kept skipping and not gripping when I put any extra pressure on the gas. I noticed an immediate difference when I installed the Potenza S-04's. I love to accelerate hard after a full stop, and the S-04's have reduced the skipping tendencies of my car by 85-90%. So far I love them, but I do worry about the tread life, which I understand will be less than that of the Kumhos. If I get 20,000 miles out of this set, I'll be happy.